case study on psychopaths

The Neuroscientist Who Discovered He Was a Psychopath

While studying brain scans to search for patterns that correlated with psychopathic behavior, James Fallon found that his own brain fit the profile

Joseph Stromberg

One afternoon in October 2005, neuroscientist James Fallon was looking at brain scans of serial killers. As part of a research project at UC Irvine, he was sifting through thousands of PET scans to find anatomical patterns in the brain that correlated with psychopathic tendencies in the real world.

“I was looking at many scans, scans of murderers mixed in with schizophrenics, depressives and other, normal brains,” he says. “Out of serendipity, I was also doing a study on Alzheimer’s and as part of that, had brain scans from me and everyone in my family right on my desk.”

James Fallon’s new book,  The Psychopath Inside

“I got to the bottom of the stack, and saw this scan that was obviously pathological,” he says, noting that it showed low activity in certain areas of the frontal and temporal lobes linked to empathy, morality and self-control. Knowing that it belonged to a member of his family, Fallon checked his lab’s PET machine for an error (it was working perfectly fine) and then decided he simply had to break the blinding that prevented him from knowing whose brain was pictured. When he looked up the code, he was greeted by an unsettling revelation: the psychopathic brain pictured in the scan was his own.

Many of us would hide this discovery and never tell a soul, out of fear or embarrassment of being labeled a psychopath. Perhaps because boldness and disinhibition are noted psychopathic tendencies , Fallon has gone all in towards the opposite direction, telling the world about his finding in a TED Talk , an NPR interview and now a new book published last month, The Psychopath Inside .  In it, Fallon seeks to reconcile how he—a happily married family man—could demonstrate the same anatomical patterns that marked the minds of serial killers.

“I’ve never killed anybody, or raped anyone,” he says. “So the first thing I thought was that maybe my hypothesis was wrong, and that these brain areas are not reflective of psychopathy or murderous behavior.”

But when he underwent a series of genetic tests, he got more bad news. “I had all these high-risk alleles for aggression, violence and low empathy,” he says, such as a variant of the MAO-A gene that has been linked with aggressive behavior. Eventually, based on further neurological and behavioral research into psychopathy, he decided he was indeed a psychopath—just a relatively good kind, what he and others call a “ pro-social psychopath ,” someone who has difficulty feeling true empathy for others but still keeps his behavior roughly within socially-acceptable bounds.

It wasn’t entirely a shock to Fallon, as he’d always been aware that he was someone especially motivated by power and manipulating others, he says. Additionally, his family line included seven alleged murderers , including Lizzie Borden , infamously accused of killing her father and stepmother in 1892.

But the fact that a person with the genes and brain of a psychopath could end up a non-violent, stable and successful scientist made Fallon reconsider the ambiguity of the term. Psychopathy, after all, doesn’t appear as a formal diagnosis in the  Diagnostic and Statistical Manual of Mental Disorders  in part because it encompasses such a wide range of symptoms. Not all psychopaths kill; some, like Fallon, exhibit other sorts of psychopathic behavior.

“I’m obnoxiously competitive. I won’t let my grandchildren win games. I’m kind of an asshole, and I do jerky things that piss people off,” he says. “But while I’m aggressive, but my aggression is sublimated. I’d rather beat someone in an argument than beat them up.”

Why has Fallon been able to temper his behavior, while other people with similar genetics and brain turn violent and end up in prison? Fallon was once a self-proclaimed genetic determinist , but his views on the influence of genes on behavior have evolved. He now believes that his childhood helped prevent him from heading down a scarier path.

“I was loved, and that protected me,” he says. Partly as a result of a series of miscarriages that preceded his birth, he was given an especially heavy amount of attention from his parents, and he thinks that played a key role.

This corresponds to recent research: His particular allele for a serotonin transporter protein present in the brain, for example, is believed to put him at higher risk for psychopathic tendencies. But further analysis has shown that it can affect the development of the ventromedial prefrontal cortex (the area with characteristically low activity in psychopaths) in complex ways: It can open up the region to be more significantly affected by environmental influences, and so a positive (or negative) childhood is especially pivotal in determining behavioral outcomes.

Of course, there’s also a third ingredient, in addition to genetics and environment: free will. “Since finding all this out and looking into it, I’ve made an effort to try to change my behavior,” Fallon says. “I’ve more consciously been doing things that are considered ‘the right thing to do,’ and thinking more about other people’s feelings.”

But he added, “At the same time, I’m not doing this because I’m suddenly nice, I’m doing it because of pride—because I want to show to everyone and myself that I can pull it off.”

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Joseph Stromberg was previously a digital reporter for Smithsonian .

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Psychopaths are not incapable of feeling emotions, like regret and disappointment, but what they cannot do is make accurate predictions about the outcomes of their choices, according to a study co-authored by Joshua Buckholtz, associate professor of psychology at Harvard.

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A revised portrait of psychopaths

Peter Reuell

Harvard Staff Writer

Study finds that they do feel regret, but it doesn’t affect their choices

When most people hear the word psychopath, they immediately think of a Hannibal Lecter–style serial killer who is cold, calculating, emotionless, willing to do or say anything to get their desire.

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And they’re not alone. For decades, researchers studying psychopathy have characterized the disorder as a profound inability to process emotions such as empathy, remorse, or regret.

A recent study , though, suggests that psychopaths are not incapable of feeling emotions like regret and disappointment. What they cannot do, it seems, is make accurate predictions about the outcomes of their choices.

The study, co-authored by Joshua Buckholtz, associate professor of psychology at Harvard, and Arielle Baskin-Sommers, assistant professor of psychology and of psychiatry at Yale University, offers a new model of the disorder that could shed important light on the decision-making process of psychopaths. The study was published in the Proceedings of the National Academy of Sciences.

“The assumption has always been that they make these bad choices because they can’t generate negative emotions like fear, or appropriately respond to emotional signals generated by other people … but we turned that idea on its head.”

Using an economic game, Buckholtz and Baskin-Sommers were able to show that while psychopaths have normal, or even enhanced, emotional responses in situations that typically elicit regret, they have trouble extracting information from the environment that would indicate that an action they’re about to take will result in the experience of regret.

“There are two components to regret,” Buckholtz explained. “There is retrospective regret, which is how we usually think about regret — the emotional experience after you learn you could have received a better outcome if you had made a different choice. But we also use signals from our environment to make predictions about which actions will or won’t result in regret. What differentiated psychopaths from other people was their inability to use those prospective regret signals, to use information about the choices they were given to anticipate how much regret they were going to experience, and adjust their decision-making accordingly.

“It’s almost like a blindness to future regret,” he added. “When something happens, they feel regret, but what they can’t do is look forward and use information that would tell them they’re going to feel regret to guide their decision-making.”

“These findings highlight that psychopathic individuals are not simply incapable of regret [or other emotions], but that there is a more nuanced dysfunction that gets in the way of their adaptive functioning,” Baskin-Sommers said. “By appreciating this complexity, we are poised to develop more accurate methods for predicting the costly behavior of psychopathic individuals.”

Using a measure of prospective regret sensitivity, Buckholtz and Baskin-Sommers were also able to predict whether and even how many times study participants had been incarcerated.

“Contrary to what you would expect based on these basic emotional-deficit models, their emotional responses to regret didn’t predict incarceration,” Buckholtz said. “We know psychopathy is one of the biggest predictors of criminal behavior, but what we found was that behavioral regret sensitivity moderated that, raising the suggestion that intact behavioral regret sensitivity could be a protective factor against incarceration in psychopathic individuals.”

While the study upends the pop-culture image of psychopaths, Buckholtz is hopeful that it will also provide a new direction for scientists who hope to understand how psychopaths make decisions.

“We actually know very little about how psychopaths make choices,” he said. “There have been all sorts of research into their emotions and emotional experience, but we know next to nothing about how they integrate information that we extract from the world as a matter of course and use it to make decisions in daily lives. Getting better insight into why psychopaths make such terrible choices, I think, is going to be very important for the next generation of psychopathy research.”

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September 1, 2010

12 min read

Inside the Mind of a Psychopath

Neuroscientists are discovering that some of the most cold-blooded killers aren't bad. They suffer from a brain abnormality that sets them adrift in an emotionless world

By Kent A. Kiehl & Joshua W. Buckholtz

The word “psychopath” conjures up movie images of brutal, inexplicable violence: Jack Nicholson chasing his family with an ax in The Shining or Anthony Hopkins as Hannibal Lecter, his face locked into an armored mask to keep him from biting people to death. But real life offers another set of images, that of killers making nice: Ted Bundy as law student and aide to the governor of Washington State, and John Wayne Gacy as the Junior Chamber of Commerce’s “Man of the Year.” Psychopaths are likable guys when they want to be.

Between the two of us, we have interviewed hundreds of prison inmates to assess their mental health. We are trained in spotting psychopaths, but even so, coming face to face with the real article can be electrifying, if also unsettling. One of the most striking peculiarities of psychopaths is that they lack empathy; they are able to shake off as mere tinsel the most universal social obligations. They lie and manipulate yet feel no compunction or regrets—in fact, they don’t feel particularly deeply about anything at all.

So much of the way regular people make sense of the world is through emotion. It informs our “gut” decisions, our connections to people and places, our sense of belonging and purpose. It is almost impossible to imagine life without feelings—until you meet a psychopath. But psychopaths often cover up their deficiencies with a ready and engaging charm, so it can take time to realize what you are dealing with.

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One of us (Kiehl) used to ask inexperienced graduate students to interview a particularly appealing inmate before acquainting themselves with his criminal history. These budding psychologists would emerge quite certain that such a well-spoken, trustworthy person must have been wrongly imprisoned. Until, that is, they read his file—pimping, drug dealing, fraud, robbery, and on and on—and went back to reinterview him, at which point he would say offhandedly, “Oh, yeah, I didn’t want to tell you about all that stuff. That’s the old me.”

This appearance of normalcy—the so-called mask of sanity—has bedeviled the study of psychopaths. Though guilty of the most erratic and irresponsible, sometimes destructive and violent behavior, they show none of the classic signs of mental illness. They don’t have hallucinations or hear voices. They aren’t confused, or anxious, or driven by overwhelming compulsions. Nor do they tend to be socially awkward. They are often of better-than-average intelligence. Add that they do not express true remorse or a desire to change, and it has been easy to view psychopaths not as victims of a dire mental instability but simply as opportunists. To paraphrase the dilemma: Are they mad or simply bad?

From the biblical Cain to the kunlangeta of the Yupi Eskimos and the arankan of Nigeria, nearly every culture on earth has recorded the existence of individuals whose antisocial behavior threatens community peace. But thanks to technology that captures brain activity in real time, experts are no longer limited to examining psychopaths’ aberrant behavior. We can investigate what is happening inside them as they think, make decisions and react to the world around them. And what we find is that far from being merely selfish, psychopaths suffer from a serious biological defect. Their brains process information differently from those of other people. It’s as if they have a learning disability that impairs emotional development.

In a collective throwing up of hands, psychiatrists have long written psychopaths off as beyond help. But now that science is unraveling the mechanisms behind the disorder, it’s time for that attitude to change. If specific physiological deficits prevent psychopaths from empathizing with others, forming stable relationships and learning from their mistakes, then elucidating them could lead to new treatments: medications, perhaps, or targeted behavioral strategies.

Kiehl has launched an ambitious multimillion-dollar project—funded by the National Institutes of Mental Health (NIMH) and Drug Abuse (NIDA) and the John D. and Catherine T. MacArthur Foundation—to gather genetic information, brain images and case histories from 1,000 psychopaths and compile it all into a searchable database. To speed the work, Kiehl helped to design a portable scanner—a functional MRI machine housed in a trailer—that can be brought inside prison walls, obviating the need for high-level clearances to bring dangerous prisoners off-site.

We believe psychopaths are as deserving of treatment as anyone with a mental illness, but you don’t have to feel sympathy to want to help them. Between 15 and 35 percent of U.S. prisoners are psychopaths. Psychopaths offend earlier, more frequently and more violently than others, and they are four to eight times more likely to commit new crimes on release. In fact, there is a direct correlation between how high people score on the 40-point screening test for psychopathy and how likely they are to violate parole. Kiehl recently estimated that the expense of prosecuting and incarcerating psychopaths, combined with the costs of the havoc they wreak in others’ lives, totals $250 billion to $400 billion a year. No other mental health problem of this size is being so willfully ignored.

Level Heads, Empty Hearts A man we will call Brad was in prison for a particularly heinous crime. In an interview he described how he had kidnapped a young woman, tied her to a tree, raped her for two days, then slit her throat and left her for dead. He told the story, then concluded with an unforgettable non sequitur. “Do you have a girl?” he asked. “Because I think it’s really important to practice the three C’s—caring, communication and compassion. That’s the secret to a good relationship. I try to practice the three C’s in all my relationships.” He spoke without hesitation, clearly unaware how bizarre this self-help platitude sounded after his awful confession.

Charming as they may seem, psychopaths can also be tone-deaf because they lack access to their own feelings and those of others. Imagine what it would be like never to be depressed or anxious, never to have regrets or low self-esteem but also never to care deeply for anyone or anything. Psychopaths’ emotions are shallow: they feel irritated when they don’t get their way and turn to risky behaviors for the flimsiest of reasons. Bereft of loyalties and passions, they wander through life, often straying into criminality on a whim—forgeries, thefts, assaults, even murders may be committed out of some trivial impulse. As for complex emotions such as devotion, guilt or joy, theirs remains a textbook understanding—it has been said that they “know the words but not the music.”

Dozens of studies reveal that psychopaths experience the world differently from other people. They have trouble making appropriate moral value judgments and putting the brakes on their impulses. They are also hampered in how they respond to emotions, language and distractions—a disconnect that is sometimes seen as early as age five.

Psychopaths are curiously oblivious to emotional cues. In 2002 James Blair of the NIMH showed that they are not good at detecting emotions, especially fear, in another person’s voice. They also have trouble identifying fearful facial expressions. And a classic experiment in 1991 co-authored by psychologist Robert D. Hare of the University of British Columbia, a pioneer in the field (and a mentor to Kiehl during graduate school), found that psychopaths miss the emotional nuances of language. The investigators flashed real and nonsense words in front of prisoners, some of whom were psychopaths, and asked them to press a button when they saw a dictionary word. Psychopaths were as quick as nonpsychopaths to differentiate between real and fabricated words. But the experiment went a level deeper, because among the real words some had positive or negative connotations (“milk,” “scar”) whereas others were neutral (“gate”). For the nonpsychopaths, emotionally charged words leaped off the screen; their automatic brain responses, measured by electroencephalograms, showed a distinctive electrical surge, and they pushed the button faster. Psychopaths did not react faster to emotional words, and their brain waves did not change.

Evidence is mounting that language bedevils psychopaths in other ways. Psychopaths have trouble understanding metaphors—for example, they are more likely than others to judge as negative the phrase “Love is an antidote for the world’s ills.” Additionally, Kiehl found in a 1999 study that psychopaths make more errors when identifying abstract nouns—words such as “love,” “deceit,” “trust,” “dedication” and “curiosity.”

Yet another deficiency of psychopaths has to do with how they pay attention. In an ingenious gambling experiment, Joseph P. Newman of the University of Wisconsin–Madison, with whom one of us (Buckholtz) has worked extensively, showed that psychopaths have trouble shifting gears, even when their current strategy for obtaining their goal is failing. Participants were given a computerized deck of 100 cards that had been arranged so that nine of the first 10 cards were face cards, eight of the next 10 were face cards, seven of the next 10 were face cards, and so forth. They were told that each time they turned over a card they would receive a point if it was a face card and lose a point if it was not. They could end the game at any time. Players earned easy points at first, but as the odds worsened, nonpsychopaths noticed and stopped playing, usually after about 50 cards. Psychopaths, on the other hand, kept on until the deck was almost finished and their winnings had vanished.

Newman believes that the apparent callousness of psychopaths is actually the result of an attentional quirk: they do not take in new information when their attention is otherwise engaged. Previous research has suggested that psychopaths are unreactive: their palms do not sweat when they are exposed to foul odors or shown images of mutilated faces. But Newman and his colleagues recently demonstrated that psychopaths actually have normal physiological responses to unpleasant stimuli, like the threat of an electric shock—except when their attention is directed elsewhere. Once fixed on a goal, psychopaths proceed as if they can’t get off the train until it reaches the station. This narrowly focused, full-speed-ahead tendency, paired with the psychopath’s impulsivity, may produce the kind of horror described in In Cold Blood : an all-night torture fest that appears almost aimless, the work of two criminals who, having begun the violence, are blind and deaf to information that might halt it (such as a victim’s pleas), unable to turn away until it has been completed.

An Altered Brain In 1848 a handsome, dark-haired young man named Phineas Gage was working as a construction foreman on the Rutland & Burlington Railroad in Vermont. He and his crew were clearing a rocky area when an accidental explosion blew Gage’s tamping iron—a heavy metal rod more than three feet long—through the left side of his face and out the top of his head. Such an injury seemed sure to kill or at the very least cripple him. But although “half a teacupful” of his brain leaked onto the floor, as the attending doctor recalled, Gage apparently never lost consciousness and on his recovery remained relatively fit. His compatriots noticed a change in him, however—one that was more disturbing than if he had lost the use of his limbs. Formerly savvy, even-tempered and responsible, Gage was now churlish and unpredictable, driven by his immediate passions. Gage’s story became a classic of neuroscience because it revealed that behavior, which seems a matter of personal will, is fundamentally biological.

Gage lost the use of a part of the brain called the ventromedial prefrontal cortex. Located behind the eyes, this area is structurally similar to its neighbor, the orbitofrontal cortex—which many scientists believe malfunctions in psychopaths. The orbitofrontal cortex is involved in sophisticated decision-making tasks that involve sensitivity to risk, reward and punishment. People whose brains are damaged in this area develop problems with impulsivity and insight and lash out in response to perceived affronts—much like Gage. In fact, such patients are often said to suffer from “acquired psychopathy.”

But transformed as Gage was by his accident, he did not show all the characteristics of psychopathy, such as lack of empathy. This fact suggests that other brain structures are also involved. One likely candidate is the almond-shaped amygdala, which generates emotions such as fear. Monkeys with amygdala damage walk right up to people. Psychopaths, too, are notable for their fearlessness: when confronted with images such as a looming attacker or a weapon aimed their way, they literally don’t blink.

But evidence suggests that one or two brain areas are not enough to produce the profound impairments of psychopaths. Kiehl recently proposed that psychopathy emanates from the paralimbic system, a group of interconnected brain structures that are involved in emotion processing, goal seeking, motivation and self-control. Supporting this hypothesis are fMRI images of psychopaths’ brains made by Kiehl and others, which show a pronounced thinning of the paralimbic tissue—indicating that this part of the brain is underdeveloped, like a weak muscle.

In addition to the orbitofrontal cortex and amygdala, the paralimbic system includes the anterior cingulate cortex and the insula. The anterior cingulate regulates emotional states and helps people control their impulses and monitor their behavior for mistakes.

The insula plays a key role in recognizing violations of social norms, as well as in experiencing anger, fear, empathy and disgust. Psychopathic behavior is by definition insensitive to social expectations, and as described earlier, psychopaths can have unusually high disgust thresholds, tolerating repellent smells and images with equanimity.

The insula is also involved in pain perception. Studies of psychopaths—including one in which subjects got electric shocks—find that, under certain conditions, they are strikingly unfazed by the threat of pain; they also have trouble noticing their errors and adjusting their behavior accordingly (which helps to explain the self-defeating way that psychopaths land in jail repeatedly, unable to learn from past mistakes).

Are psychopaths made or born? The answer is probably both. If, as investigators believe, genes account for 50 percent of the variability among those who exhibit adult antisocial traits, that means life circumstances are just as important as biological inheritance. Some psychopaths are scarred by rough childhoods, but others are the “black sheep” of stable families. Regardless of whether genes or environment has the greater influence, early intervention—perhaps even in preschool—could be critical. Just as there is a moment in childhood when the brain is primed to learn language, a task that becomes much harder later on, we suspect there may be an early window for developing the social and cognitive skills that underlie what we call “conscience.”

Ignored at Our Peril Psychopaths are misunderstood. This fact may not tug at the heartstrings, but it is a problem for all of us. Some researchers have estimated that as many as 500,000 psychopaths inhabit the U.S. prison system, and there may be another 250,000 more living freely—perhaps not committing serious crimes but still taking advantage of those around them. Helping them manage their impulsivity and aggression could protect many innocents. Until now, though, few efforts have been made in that direction. Billions of research dollars have been spent on depression; probably less than a million has been spent to find treatments for psychopathy. In part, psychologists have been turned off by evidence that psychopaths are untreatable. For example, some studies show that after receiving group therapy in prison, psychopaths are more likely to commit new crimes than if they had received no treatment at all. Listening to others bare their soul is clearly not a good strategy: psychopaths are notoriously good at learning and exploiting the weaknesses of others. They also have trouble absorbing abstract ideas, so lectures about personal responsibility are unlikely to penetrate.

But there is room for optimism: a new treatment for intractable juvenile offenders with psychopathic tendencies has had tremendous success. Michael Caldwell, a psychologist at the Mendota Juvenile Treatment Center in Madison, Wis., uses intensive one-on-one therapy known as decompression aimed at ending the vicious cycle in which punishment for bad behavior inspires more bad behavior, which is in turn punished. Over time, the incarcerated youths in Caldwell’s program act out less frequently and become able to participate in standard rehabilitation services.

A group of more than 150 youths treated by Caldwell were 50 percent less likely to engage in violent crime afterward than a comparable group who were treated at regular juvenile corrections facilities. The young people in the regular system killed 16 people in the first four years after their release; those in Caldwell’s program killed no one. The economic benefits are also huge: for every $10,000 society spends on treatment, we save $70,000 that would have been required to keep those people in jail.

The ongoing brain and genetic studies are likely to further improve Caldwell’s results: perhaps, as with depression, a combination of therapy and medication will prove especially potent. But such advances are slowed by the fact that psychopathy is often overlooked by the mental health mainstream. It isn’t even included in the Diagnostic and Statistical Manual of Mental Disorders —the DSM —an exhaustive catalogue of more than 300 known psychiatric conditions that serves as the clinician’s bible. The DSM’s framers instead created a catchall diagnosis for the criminally inclined, known as antisocial personality disorder, and left it at that.

Why was psychopathy excluded? The creators of the DSM may have felt that it would be too difficult for the average therapist to make an accurate diagnosis: after all, psychopaths are sure to lie convincingly during the interview.

Whatever the reasons, many psychiatrists are left with the false impression that psychopathy and antisocial personality disorder are the same. They are not. Antisocial personality disorder is a helpful diagnosis when the question is whether a person is likely to behave badly, but it does nothing to discriminate among criminals. Only one in five people with antisocial personality disorder is a psychopath. Yet time and again at trial, experts wrongfully attest that when a defendant has antisocial personality disorder, it means he is a psychopath, which in turn means he is likely to reoffend and should not be paroled.

As scientists continue to describe the brain dysfunctions of psychopaths, the revelations promise not only to aid disturbed individuals but to bring sanity to society. For it is senseless to ignore psychopaths when they pose such a threat. When lawyers, jailers, psychiatrists and others begin to see psychopaths for what they are—not monsters but people whose emotional disabilities may cause them to act monstrously—we will all be on the path to a safer future.

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Review article, what can we learn about emotion by studying psychopathy.

• Department of Psychology, Georgetown University, Washington, DC, USA

Psychopathy is a developmental disorder associated with core affective traits, such as low empathy, guilt, and remorse, and with antisocial and aggressive behaviors. Recent neurocognitive and neuroimaging studies of psychopathy in both institutionalized and community samples have begun to illuminate the basis of this condition, in particular the ways that psychopathy affects the experience and recognition of fear. In this review, I will consider how understanding emotional processes in psychopathy can shed light on the three questions central to the study of emotion: (1) Are emotions discrete, qualitatively distinct phenomena, or quantitatively varying phenomena best described in terms of dimensions like arousal and valence? (2) What are the brain structures involved in generating specific emotions like fear, if any? And (3) how do our own experiences of emotion pertain to our perceptions of and responses to others' emotion? I conclude that insights afforded by the study of psychopathy may provide better understanding of not only fundamental social phenomena like empathy and aggression, but of the basic emotional processes that motivate these behaviors.

Emotion is the major driver of all human and animal behavior, including social behavior—it is emotion that literally moves us to seek or escape positive and negative consequences ( LeDoux, 2012 ). Many unanswered questions remain about the nature of human emotion and are the topic of vibrant ongoing debates: are different emotions qualitatively distinct, emerging from separable neurobiological processes, or can emotions be more accurately described dimensionally in terms of arousal and valence ( Russell and Barrett, 1999 ; Barrett et al., 2007 ; Izard, 2007 ; Panksepp, 2007 ; LeDoux, 2012 )? If distinct neurobiological events contribute to the generation of different emotions, which brain structures are most relevant to the emergence of these emotions ( Panksepp, 2007 ; Vytal and Hamann, 2010 ; Lindquist et al., 2012 )? And finally, how do emotions we experience pertain to our perceptions of and responses to emotions in others ( Zahavi, 2008 ; Heberlein and Atkinson, 2009 )?

Answering these questions about human emotion presents a variety of challenges. Unlike the study of some other human cognitive processes, the study of emotion benefits from the now widely accepted fact that humans and non-human animals share many emotional processes, enabling more, and more diverse study paradigms on emotion ( Panksepp, 2007 ; Panksepp and Lahvis, 2011 ; LeDoux, 2012 ). A benefit of studying non-human animals is that they enable critical experimental manipulations to be performed, such as environmental manipulations that cause intense, ecologically valid experiences like fear, and manipulations of subcortical brain structures involved in emotion, such as permanent or temporary lesions or genetic manipulations. Gray and McNaughton argue that such techniques are essential for drawing causal inferences about some emotional processes ( Gray and McNaughton, 2000 ). However, animals can provide little information relevant other critical features of emotion, such as information about subjective experiences. Research in humans can target subjective experience, but, conversely, many critical experimental manipulations of emotion are not feasible or ethical to perform in humans, such as intense, ecologically valid environmental manipulations or lesions to subcortical structures.

One means of circumventing this conundrum is to conduct research in individuals affected by pathologies that provide “natural experiments” in which emotional processes are altered, enabling identification of the downstream effects. One example is the use of case studies of individuals with lesions to specific brain regions as a result of disease, injury, or surgical intervention, such as the orbitofrontal cortex ( Hornak et al., 2004 ), insula ( Phillips et al., 1997 ), or amygdala ( Feinstein et al., 2011 ). Such cases can yield rich and detailed evidence about the emotional processes subserved by the damaged region. The downside is that individuals in whom lesions are neuroanatomically specific enough to yield meaningful evidence are rare. Thus, few researchers have access to these patients, and the possibility persists that certain response patterns result from patient-specific idiosyncrasies unrelated to the lesion. In addition, most brain lesions occur in late adolescence or adulthood, precluding an understanding of the developmental consequences of lesions to structures like the amygdala, damage to which may result in distinct behavioral outcomes in adulthood relative to infancy ( Amaral, 2003 ).

An alternative to lesion-based case studies is the study of populations of patients affected by psychopathologies known to affect specific neurocognitive systems. Psychopathy, a cluster of behavior tendencies and personality traits associated with callousness and antisocial behavior, is one such form of psychopathology ( Hare, 1993 ; Blair et al., 2006 ; Skeem et al., 2011 ). Evidence is accumulating to suggest impairments in the systems and processes supporting fear responding in psychopathy, leaving other systems largely intact ( Lilienfeld et al., 2012 ; Patrick et al., 2012 ; Rothemund et al., 2012 ). Psychopathy may therefore be a useful empirical tool for understanding the nature of fear and perhaps emotion more broadly.

In this review, I will consider how understanding psychopathy can shed light on the three questions outline above: (1) Are emotions discrete, qualitatively distinct phenomena or quantitatively varying phenomena best described in terms of dimensions like arousal and valence? (2) What are the brain structures involved in generating specific emotions like fear, if any? And (3) how do our own experiences of emotion pertain to our perceptions of and responses to others' emotion?

Psychopathy

Psychopathy is a disorder that is generally viewed as the confluence of core personality characteristics plus antisocial behavioral tendencies, and which, in its extreme form, affects 1–2% of the general population and as many as 50% of violent offenders ( Hare, 1993 ; Rutter, 2012 ). The core personality features associated with psychopathy are callous and unemotional personality traits, which include a lack of empathy or remorse, weak social bonds, an uncaring nature, and shallow emotional responding ( Cooke et al., 2005 ; Frick and White, 2008 ; Viding and McCrory, 2012 ). The antisocial behavior tendencies that tend to accompany these traits include poor control of anger, impulsiveness, irresponsibility, and a parasitic orientation toward others ( Frick and Ellis, 1999 ). These factors are generally positively related, such that higher levels of callous and unemotional personality traits predict increased antisocial behavior ( Viding et al., 2007 ; Kahn et al., 2013 ). The presence of psychopathic traits are particularly strong predictors of aggression that serves an instrumental goal, such as bullying, sexual violence, or assault during the course of a robbery ( Blair, 2001 ; Woodworth and Porter, 2002 ). Debates persist as to whether the features of psychopathy are best classified using various two-, three-, and four-factor models that have been proposed ( Jones et al., 2006 ; Skeem et al., 2011 ), and whether criminal or aggressive behavior is an essential part of the psychopathy construct ( Hare and Neumann, 2010 ; Skeem and Cooke, 2010 ), however, the basic features that compose the construct of psychopathy are generally agreed upon.

Psychopathy is not a clinical diagnosis in the Diagnostic and Statistical Manual (DSM-IV-TR), although features of psychopathy are incorporated into the Axis II diagnosis Antisocial Personality Disorder ( Lynam and Vachon, 2012 ). Various suggestions for updating the DSM 5 to reflect current conceptualizations of psychopathy in adults and children have been proposed ( Frick and Moffitt, 2010 ; Skodol et al., 2011 ). That said, emerging evidence suggests that psychopathy is not taxonomic in structure. As is the case for traits that comprise other forms of mental illness ( Markon et al., 2011 ), psychopathic traits appear to be continuously distributed in the population and can be most reliably and validly assessed when treated as a continuous rather than a discrete measure ( Edens et al., 2006 ; Guay et al., 2007 ; Kotov et al., 2011 ). This is important because it suggests that information about psychopathy can be drawn from both clinically diagnosed samples and community samples ( Malterer et al., 2010 ).

Psychopathy affects both children and adults. Markers of psychopathy may emerge early in childhood ( Glenn et al., 2007 ; Wang et al., 2012 ), are moderately reliable predictors of adult psychopathy ( Lynam et al., 2008 ), and the core affective features of psychopathy appear to be highly heritable ( Larsson et al., 2006 ). The heritability coefficient of the core callous and unemotional features has been estimated to be at least 0.43 ( Larsson et al., 2006 ) and as high as 0.71 ( Viding et al., 2005 , 2008 ). An individual's risk for engaging in antisocial behavior during childhood or adulthood can be increased by any number of life history events, including trauma exposure, low socioeconomic status, or delinquent peer groups ( Lynam et al., 2008 ), but these factors do not seem to precipitate the emergence of psychopathic traits in children (often termed callous-unemotional traits). In fact, callous-unemotional traits may paradoxically serve as a protective factor against parental maltreatment: among children with callous-unemotional traits, there is little correspondence between the quality of parenting that children receive and the severity of their antisocial behavior problems ( Wootton et al., 1997 ). Instead it appears that life stressors that result in heightened stress responding represent a distinct etiological route toward antisocial behavior ( Blair, 2001 ). Among children without high levels of callous-unemotional traits, parental maltreatment is associated with increased antisocial behavior ( Wootton et al., 1997 ). In addition, antisocial behavior in the absence of callous-unemotional traits does not appear to be highly heritable, supporting the role of environmental stressors in leading to antisocial behavior in the absence of callous-unemotional traits ( Viding et al., 2005 , 2008 ).

Psychopathy and Fear Responding

From the earliest formal clinical descriptions of psychopathy, the construct has been linked to deficient fear responding. Most modern conceptualizations of psychopathy are based on the work of Cleckley (1988) , whose compiled observations of institutionalized psychopaths are described in The Mask of Sanity . He distinguishes psychopaths from other psychiatric patients as typically free from delusions or irrational thinking, suicidality, or other self-harm tendencies, and, in particular, from anxiety or fear. The second criterion Cleckley specifies for identifying psychopathy is an, “Absence of nervousness or psychoneurotic manifestations,” and he describes the prototypical psychopath as “incapable of anxiety” (p. 340) showing “immunity from … anxiety or worry” (p. 339), and being “free from … nervousness” (p. 339).

Although Cleckley's descriptions of psychopathy reflect a psychodynamic orientation, his observations are consistent with more recent experimental data assessing fear responding in psychopathy. A focus on fear responding emerged from the observation that psychopathic offenders are particularly likely to re-offend, suggesting that the threat of future punishments is not sufficiently motivating for them ( Corrado et al., 2004 ; Hare, 2006 ). Fear is, in essence, the state that accompanies the anticipation of an aversive outcome (i.e., punishment) and promotes avoidance and escape behaviors ( Stein and Jewett, 1986 ; Panksepp, 1998 ; LeDoux, 2000 ). Fear being the emotion that promotes avoidance of behaviors that result in punishment ( LeDoux, 2003 ), it is ostensibly is the mechanism by which punishing criminal behavior serves to deter it. Early hypotheses proposed that dysfunctional fear responding renders psychopaths less likely to avoid engaging in criminal behaviors that result in punishments like imprisonment, and were supported by laboratory findings that psychopaths are less likely to modulate their behavior in response to anticipated punishments ranging from electrical shock to loss of points in a computer game ( Lykken, 1957 ; Hare, 1966 ; Newman and Kosson, 1986 ; Blair et al., 2004 ).

Abundant psychophysiological research supports the notion that psychopaths' responses to the threat of an aversive outcome are muted. Psychopathy impairs anticipatory skin-conductance responses ( Lykken, 1957 ; Aniskiewicz, 1979 ; Herpertz et al., 2001 ; Birbaumer et al., 2005 ; Rothemund et al., 2012 ), fear-potentiated startle responses ( Patrick et al., 1993 ; Levenston et al., 2000 ; Herpertz et al., 2001 ; Rothemund et al., 2012 ), and contraction of the corrugator muscle underlying the brows ( Herpertz et al., 2001 ; Rothemund et al., 2012 ) during threat anticipation. Psychopathy also impairs aversive classical conditioning ( Flor et al., 2002 ) as well as other fear-relevant responses such as the recognition of fear from the face, body, and voice ( Marsh and Blair, 2008 ; Dawel et al., 2012 ). These differences are particularly evident for psychopathic offenders characterized as “primary” psychopaths who exhibit the core callous and unemotional personality features of the disorder ( Lykken, 1957 ; Aniskiewicz, 1979 ; Dawel et al., 2012 ). This is in contrast to “secondary” psychopaths, in whom antisocial behavior may primarily reflect social disadvantage or maltreatment and who may present with increased anxiety ( Newman et al., 2005 ; Kimonis et al., 2012 ).

Finally, both anecdotal reports and empirical evidence indicate that subjective experiences of fear are reduced in psychopathy. In Without Conscience ( Hare, 1993 ), Hare describes an interview with a psychopathic offender who seemingly fails to understand the fundamental nature of fear:

Another psychopath … said that he did not really understand what others meant by “fear.” However, “When I rob a bank,” he said, “I notice that the teller shakes or becomes tongue-tied. One barfed all over the money. She must have been pretty messed up inside, but I don't know why. If someone pointed a gun at me, I guess I'd be afraid but I wouldn't throw up.” When asked to describe how he would feel in such a situation, his reply contained no references to body sensations. He said things such as, “I'd give you the money”; “I'd think of ways to get the drop on you”; “I'd try and get my ass out of there.” When asked how he would feel , not what he would think or do, he seemed perplexed. Asked if he ever felt his heart pound or his stomach churn, he replied, “Of course! I'm not a robot. I really get pumped up when I have sex or when I get into a fight” (pp. 53–54).

Also supporting reduced subjective experience of fear in psychopathy are the results of a recent study in which adolescents with psychopathic traits and healthy controls underwent an autobiographical recall paradigm adapted from a task developed to measure subjective experiences of emotion across cultures ( Scherer and Wallbott, 1994 ). In the task, participants described recent emotionally evocative events and their subjective responses during these events. This paradigm has the advantage of using a single measure to assess responses to five emotional states. Relative to controls, adolescents with psychopathic traits reported reduced symptoms of sympathetic nervous system activation, such as changes in breathing or muscle tension, during fear-evoking events, even though judges rated the psychopathic adolescents' descriptions of the fear-evoking events as no less inherently frightening than the events reported by controls. In addition, psychopathic adolescents reported that in daily life they experience fear less often and less intensely than did controls ( Marsh et al., 2011 ). Two adolescents with psychopathic traits in this study reported never having felt fear, an experience not reported by any of the healthy adolescents.

In keeping with this pattern, many contemporary assessments of psychopathy specifically index items related to reduced anxiety and fearfulness. These measures include the Triarchic Psychopathy Measure, e.g., “I'm afraid of far fewer things than most people” ( Patrick, 2010 ); the Youth Psychopathy Inventory e.g., “What scares others usually doesn't scare me” ( Andershed et al., 2002 ); and the Psychopathic Personality Inventory, e.g., “I can remain calm in situations that would make many other people panic” ( Lilienfeld and Andrews, 1996 ). Researchers who use psychopathy measures that do not explicitly include anxiety and fear-relevant items often supplement the scale with anxiety measures or clinical assessments of anxiety disorders ( Sutton et al., 2002 ; Finger et al., 2008 ; Malterer et al., 2008 ; Marsh et al., 2008 ; Kimonis et al., 2012 ; Koenigs et al., 2012 ).

In contrast to fear, other forms of emotional responding in psychopathy appear to be spared. The clearest example is anger, which appears intact and perhaps enhanced in psychopathy. Anger can be defined as the high arousal state that follows frustration or perceived threat and, behaviorally, is closely linked to aggression against the source of frustration or threat ( Blair, 2012 ). Elevated anger responding is intrinsic to many descriptions of psychopathy. Both Cleckley and Hare's case studies include numerous descriptions of psychopaths whose misbehavior included frequent temper tantrums and rage-induced aggression. And contemporary measures of psychopathy universally feature items that index frequent, heightened, or undercontrolled displays and experiences of anger. These measures include the youth and adult variants of the Psychopathy Checklist, e.g., “Poor anger control” ( Forth et al., 2003 ); the Antisocial Processes Screening Device, e.g., “Becomes angry when corrected or punished” ( Frick and Hare, 2001 ); the Levenson Self-Report Psychopathy Scale, e.g., “When I get frustrated, I often ‘let off steam’ by blowing my top” ( Levenson et al., 1995 ), and the Psychopathic Personality Inventory, e.g., “From time to time I really ‘blow up’ at other people” ( Lilienfeld and Andrews, 1996 ). That these criteria are positively correlated with the overall construct reinforces the positive relationship between psychopathy and anger experiences.

In psychopathy, anger is most likely to result from goal frustration rather than perceived threat ( Blair, 2012 ), although it should be noted that considerably less empirical research has assessed anger responding in psychopathy compared to fear. That said, three recent studies have found psychopathy to be associated with intact or heightened anger responding both physiologically and subjectively. Hicks and Patrick (2006) evaluated angry responding using a series of self-report scales and found elevated anger responding in psychopathy, with closer associations found between angry responding and the antisocial behavior subscale. In a similar vein, Blackburn and Lee-Evans (2011) found that psychopathic participants anticipated that they would respond with greater anger than non-psychopaths to a variety of anger-inducing scenarios. Lobbestael et al. (2009) performed an anger induction task in individuals with Antisocial Personality Disorder (who varied in psychopathic traits), Borderline Personality Disorder and controls. The induction task entailed recalling a situation in which subjects had experienced a conflict with another person and had felt very angry, after which subjects spent several minutes recalling the details of the event. Results indicated that neither total psychopathy scores nor callous and unemotional personality trait scores among individuals with antisocial personality disorder were predictive of physiological changes during the anger induction task, suggesting an intact anger response. Other studies have found no group differences in responses linked to anger, such as the study assessing subjective experiences of emotion in psychopathic adolescents and controls ( Marsh et al., 2011 ), and the results of two meta-analyses assessing the recognition of anger from the face, body, or voice ( Marsh and Blair, 2008 ; Dawel et al., 2012 ).

A second emotional state that appears to be intact in psychopathy is positive excitement. This state can be distinguished from happiness, which is more closely associated with goal attainment, as the state that accompanies the anticipation of an appetitive outcome (i.e., reward) and promotes acquisition or achievement of the reward —a state that is in some ways a mirror image of fear and that has been alternately termed wanting, seeking, or interest ( Berridge et al., 2009 ). The quotation from the incarcerated psychopath above is suggestive of the presence of positive excitement in psychopathy, and is consistent with clinical observations and empirical data that psychopaths are positively motivated by the prospect of reward, particularly near-term reward. Cleckley's criteria include several items that describe unrestrained goal-seeking in the context of money, sexual gratification, and other rewards ( Cleckley, 1988 ). And, as is true for anger, contemporary measures of psychopathy feature items related to the experience of wanting, seeking, and excitement, including the Psychopathy Checklist, e.g., “Stimulation seeking” ( Forth et al., 2003 ); the Youth Psychopathy Inventory, e.g., “If I get the chance to do something fun, I do it no matter what I had been doing before” ( Andershed et al., 2002 ); the Levenson Self-Report Psychopathy Scale, e.g., “My main purpose in life is getting as many goodies as I can” ( Levenson et al., 1995 ), and the Psychopathic Personality Inventory, e.g., “If I were a firefighter, I think I might actually enjoy the excitement of trying to rescue someone from the top floor of a burning building” ( Lilienfeld and Andrews, 1996 ). Empirical behavioral data also exist to suggest that the motivational salience of rewarding stimuli is similar to that of comparison samples ( Blair et al., 2004 ) or perhaps even increased ( Scerbo et al., 1990 ; Bjork et al., 2012 ). Because positive excitement is not always included on lists of basic emotion it is subject to less focused research than emotions like anger and fear. However, what evidence exists suggests that this state is intact or heightened in psychopathy.

There is very little evidence available that describes other types of emotional reactions in psychopathy, although what evidence exists suggests that disgust responding remains intact, and there is little evidence for consistent impairments in happiness or surprise ( Marsh and Blair, 2008 ; Marsh et al., 2011 ; Dawel et al., 2012 ). One emotion for which the present literature is genuinely ambiguous is sadness, with meta-analytic findings generally showing some deficits in recognizing sadness expressions in psychopathy, albeit less consistently and with generally smaller effect sizes than for fear. Very little literature explores sadness responses in psychopathy in other contexts, and results from these studies are equivocal (e.g., Blair et al., 1995 ; Brook and Kosson, 2013 ) In general, the neurobiological basis of sadness is not as well understood as that of fear, and further development of the neurocognitive basis of sadness may be required to develop targeted tasks assessing it in psychopaths.

It should be noted that among Cleckley's original criteria is “General poverty in major affective reactions” which is reflected in items measuring shallow affect in contemporary measures such as the PCL variants and APSD ( Hare, 1991 ; Frick and Hare, 2001 ). However, Cleckley's emphasis is primarily the quality of the anger, excitement, etc. that psychopaths experience—how long-lasting these states are, how consistent, and how “mature” their expression. Thus, whereas psychopaths may display outward signs of rage and become “vexed,” “peevish,” or “resentful,” Cleckley proposes that they do not experience “mature, wholehearted anger” ( Cleckley, 1988 , p. 348). The lability or consistency of affective reactions in psychopathy may be an important feature of the disorder. However, it remains the case that among basic emotions, only in the case of fear does strong, consistent empirical evidence support the existence of deficits in psychopathy.

Are Emotions Discrete Natural Kinds or Constructed using Dimensions of Core Affect?

These patterns of observed emotional responding in psychopathy may help to explicate a central ongoing question about emotion, namely: can emotions be better described as qualitatively distinct, for example, as discrete “basic emotions” or “natural kinds” ( Ekman et al., 1983 ; Izard, 1992 ; Panksepp, 2005 ) or as quantitatively distinct, for example, as points along a circumplex defined by dimensions like arousal and valence ( Russell and Barrett, 1999 ; Barrett and Wager, 2006 )? Recent years have seen a protracted debate in the literature about how to most accurately capture the nature of emotion ( Barrett et al., 2007 ; Izard, 2007 ; Panksepp, 2007 ; Tracy and Randles, 2011 ), with proposed models of emotion including not only basic emotion and dimensional models, but also those that focus upon goal-relevant appraisals of emotional stimuli ( Moors et al., 2013 ), emotions as coping responses ( Roseman, 2013 ), and emotions as survival circuits ( LeDoux, 2012 ). An extended conversation about the strengths and weaknesses of these various views will not be reviewed in full here, rather, the focus will be on the basic consideration of whether different emotions (e.g., fear, anger) are best viewed as qualitatively or quantitatively distinct.

Models that posit emotions to be qualitatively distinct, such as “basic emotion” models, holds that a limited number of emotions like fear, anger, and positive excitement emerge from dissociable neurophysiological processes ( Ekman et al., 1983 ; Izard, 1992 ; Panksepp, 2005 ; Lench et al., 2011 ). These neurophysiological processes are generally linked to activity in the evolutionarily ancient subcortical structures of the midbrain, striatum, and limbic system most commonly linked to emotion ( Panksepp, 2005 ; Vytal and Hamann, 2010 ). So, for example, the generation of positive excitement is linked to activation in a striatal circuit centered on dopaminergic neurons in the nucleus accumbens ( Ikemoto and Panksepp, 1999 ), whereas the generation of fear is associated with activity in a circuit involving the periaqueductal gray, anterior and medial hypothalamus, and amygdala ( LeDoux, 2000 ). In this view, finer gradations of experience result when basic emotions are modulated or elaborated by higher-level cognitive processes controlled by the cerebral cortex, but the emergence of qualitatively distinct emotions is not dependent on these cortically-controlled processes ( Panksepp, 2005 ).

Models that posit emotions to be quantitatively distinct hold that emotions like fear, anger, and happiness are best described as points on one or more core dimensions. Core dimensions typically proposed to distinguish among emotions are physiological arousal or activation (low—high) and valence (bad—good) ( Bradley et al., 2001 ). [Some have proposed a withdrawal—approach dimension as a substitute or supplement to the valence axis ( Wager et al., 2003 ; Christie and Friedman, 2004 ; van Honk and Schutter, 2006 )]. Arranged orthogonally, these dimensions form a circumplex upon which emotions can be plotted and quantitatively compared ( Barrett and Russell, 1999 ; Russell and Barrett, 1999 ; Colibazzi et al., 2010 ). Positive excitement is plotted as high in arousal and positive in valence, and sadness is low in arousal and negative in valence. Fear is typically plotted as high arousal and strongly negative, as is anger ( Russell and Barrett, 1999 ). Further distinctions among emotions are thought to reflect differences in cognitive construals of the events surrounding the basic changes in arousal and valence. Thus, whether an individual experiences anger or fear (which are similar in terms of arousal or valence) may be shaped by interpretations of neurophysiological changes in valence and arousal in light of the eliciting stimulus and the individual's idiosyncratic stores of semantic knowledge, memories, and behavioral responses that shape the subjectively experienced state ( Russell, 2003 ). Under this view, distinctions among experienced emotional states are highly dependent on these cognitively complex processes, which are subserved by a distributed network of regions of the cerebral cortex ( Lindquist et al., 2012 ).

These models generate distinct predictions to the question of whether a disorder or lesion could result in a single emotion being disabled without affecting the experience of other emotions. The discrete emotions view would argue that a disorder or lesion that resulted in dysfunction in the specific structures subserving a particular emotion could affect the experience of one emotion while leaving others intact. In contrast, the dimensional view would require either that other emotions that are dimensionally similar to the affected emotion also be affected, or that deficits in a particular emotion would reflect dysfunction in cortically-driven higher-level cognitive processes.

The case of psychopathy lends clear support to notion that fear is qualitatively distinct from other emotions. In psychopathy, the bulk of the clinical and empirical evidence points toward the conclusion that fear responding is uniquely disabled, with other high-arousal (positive excitement, anger) and negatively valenced (anger, disgust) emotions remaining intact. The dimensional view cannot easily explain why in psychopaths the high arousal, negatively valenced state of anger is easily (perhaps too easily) generated, whereas the high arousal, negatively valenced state of fear is not. The problem cannot lie in a failure to fully engage neurocognitive systems underlying either the arousal or valence dimension, because psychopaths experience other high-arousal emotions (positive excitement) as well as other negatively valenced emotions (disgust). It also cannot result from some difficulty arising at the interaction of these axes, because anger and fear are highly similar in terms of both dimensions. Models that substitute a withdrawal—approach axis for a negative—positive axis are no more successful; the two most strongly withdrawal-linked emotions are disgust and fear, and there is no evidence for disgust-based impairments in psychopathy.

Can cognitive construals of emotion explain the patterns observed in psychopathy? Perhaps, one could argue, psychopaths under threat are less likely to construe their negative, high-arousal state as fear and more likely to construe it as anger compared to non-psychopaths. So, for example, the psychopath whose interview is transcribed above might interpret a pounding heart and churning stomach as the angry response that accompanies a tendency to respond aggressively. Another person might interpret the same body symptoms as the fear that accompanies a tendency to escape or submit. Theoretically, this explanation could explain both the deficits in fear and a concomitant increase in anger in this population. One could argue that, particularly for studies that focus on subjective reports of emotion, group differences in construal underlie the tendency of psychopaths to underreport experiencing fear and overreport experiencing anger.

This argument suffers two shortcomings. First, it is inconsistent with psychophysiological findings of overall reduced arousal during threat anticipation in psychopathy. As described above, there are two major categories of anger elicitors: perceived threat and goal frustration ( Blair, 2012 ). The construal argument would require that psychopaths experience arousal in response to threat, but interpret this arousal as anger rather than fear. But the evidence is clear that psychopaths (particularly primary psychopaths) are no more likely than average to experience physiological arousal under conditions of threat ( Blackburn and Lee-Evans, 2011 )—and in fact, as described previously, show reduced physiological responses, including reduced skin conductance, potentiated startle, and corrugator muscle activity. This suggests that threat anticipation results in neither fear nor anger in this population. Psychopaths are, however, more likely than average to experience anger is in response to frustration ( Blair, 2012 ). Thus, rather than being chronically likely to construe any high arousal state as anger, psychopaths appear more likely to experience anger primarily in response to frustrated attempts to achieve a reward. That both frustration-based anger and positive excitement (the state that reflects the anticipation of reward) are normal or elevated in psychopathy is consistent with the notion that in psychopaths the systems that govern anticipation of reward are functional and perhaps even overactive while the systems that govern threat anticipation are dysfunctional. A further concern is that the construal explanation of emotion leaves unclear why psychopathy might engender such a dramatic shift in emotional experience. Such a phenomenon is particularly difficult to explain in light of the high heritability coefficient found for psychopathy. Cognitive construals of emotional states are thought to reflect the individual's autobiographical memories and semantic knowledge of emotion prototypes, phenomena that are necessarily a result of learning, rendering it unlikely that the tendency to construe one's emotional response to an event as fear versus anger would itself be heritable.

The pattern of reduced fear responding to anticipated threat observed in psychopathy, then, is more consistent with the view that states like anger and fear reflect biologically coherent and qualitatively distinct responses to particular eliciting stimuli. Dimensions like valence and arousal are useful means of quantitatively describing differences among subjective feeling states like fear, anger, and positive excitement, but may not accurately reflect the neurobiological origins of those states.

What are the Brain Structures Involved in Generating Specific Emotions Like Fear?

If psychopathy is associated with specific deficits in fear responding, this not only supports the idea that emotions are qualitatively distinct, it supports the corollary that specific neurophysiological processes that support the fear response are also affected. A key feature of models of discrete emotions is that distinct emotions have dissociable neurophysiological correlates ( Vytal and Hamann, 2010 ). Ekman (1999) has argued:

The distinctive features of each emotion, including the changes not just in expression but in memories, imagery, expectations, and other cognitive activities, could not occur without central nervous system organization and direction. There must be unique physiological [CNS] patterns for each emotion (p. 50).

Limited evidence exists to suggest specific patterns of peripheral nervous system activity that accompany discrete emotions ( Ekman et al., 1983 ; Christie and Friedman, 2004 ), however, assuming that the origins of basic emotions are in the central nervous system, most research in this vein has focused on the central origins of emotions, specifically, the structures or networks of brain structures in which activity supports the emergence of particular emotions ( Panksepp, 2007 ; Vytal and Hamann, 2010 ; Lindquist et al., 2012 ).

The availability of non-human animal analogues has made fear one of the best-studied emotions on a neuroanatomical level. On the whole, the empirical data support the idea that the amygdala, along with its efferent projections, is an essential structure for the generation of conditioned fear responses, which account for the majority of experienced fear ( Davis, 1992 , 1997 ). [Unconditioned fear in response to specific events like carbon dioxide-induced air hunger may rely on distinct neural pathways ( Johnson et al., 2011 ; Feinstein et al., 2013 )]. Extensive early evidence demonstrated that the amygdala plays a crucial role in the creation of conditioned fear in rodents. For example, lesions to the amygdala prevent rats from developing a conditioned fear response, like freezing in response to a stimulus that predicts shock ( Blanchard and Blanchard, 1972 ). Later studies clarified the roles of the various subnuclei of the amygdala, demonstrating that the lateral nucleus is primarily involved in the acquisition of the fear response whereas the central nucleus is involved in both the acquisition and the expression of conditioned fear responses ( Davis, 1992 ; Wilensky et al., 2006 ). The amygdala's many efferent projections coordinate autonomic and behavioral responses to fear eliciting stimuli. Projections from the central nucleus of the amygdala to the lateral hypothalamus are involved in activating autonomic sympathetic nervous system responses, and projections to the ventrolateral periaqueductal gray direct the expression of behavior responses, such as defensive freezing ( Davis, 1992 ; LeDoux, 2012 ). The amygdala's central role in coordinated fear responding can be demonstrated by electrical stimulation studies showing that complex patterns of behavioral and autonomic changes associated with fear responses result from stimulation of the relevant regions of the amygdala ( Davis, 1992 ). Heavy reliance on animal models is justified in the study of fear responding and the amygdala given how strongly conserved the amygdala nuclei involved in responding to conditioned threats are across species ranging from reptiles to birds to rodents to primates ( LeDoux, 2012 ).

Ethical and pragmatic considerations prevent experimental paradigms employing electrical stimulation or ablation of the amygdala from being undertaken in human subjects. However, the advent of neuroimaging technologies have enabled considerable assessments of subcortical responses to a variety of emotional stimuli, enough to provide a basis for seven meta-analyses that have been conducted to assess patterns of brain activation in response to specific emotions ( Phan et al., 2002 ; Murphy et al., 2003 ; Kober et al., 2008 ; Sergerie et al., 2008 ; Fusar-Poli et al., 2009 ; Vytal and Hamann, 2010 ; Lindquist et al., 2012 ). The findings from four of these meta-analyses support the role of the amygdala in human fear responding. Phan and colleagues reviewed 55 PET and fMRI studies (including 13 that assessed fear responding) and found that fear specifically activated the amygdala relative to other emotions ( Phan et al., 2002 ). Sixty percent of studies assessing fear responses observed an increased amygdala response whereas fewer than 25% of other emotional tasks resulted in amygdala activation increases. Murphy and colleagues reviewed 106 PET and fMRI studies ( Murphy et al., 2003 ) and again observed the most consistent amygdala responses during the induction or perception of fear relative to other emotions, interpreting their data as consistent with amygdala specialization for fear. In neither meta-analysis was any other structure observed to be consistently and selectively activated during fear paradigms. Fusar-Poli and colleagues included only fMRI studies assessing responses to emotional faces, but again found heightened amygdala responses to fearful faces relative to other emotional faces ( Fusar-Poli et al., 2009 ). Finally, Vytal and Hamann (2010) employed a more sensitive meta-analytic method, activation likelihood estimation (ALE), to analyze the results of 83 PET and fMRI studies of emotion (including 37 that assessed fear responding) and again found strong support that the amygdala is preferentially active during fear paradigms, and this activation in this region differentiated fear from happiness, sadness, and disgust.

Three recent meta-analyses did not yield findings that fear is preferentially associated with amygdala activation. Two were conducted by Feldman-Barrett and colleagues ( Kober et al., 2008 ; Lindquist et al., 2012 ). In the more recent analysis, Lindquist and colleagues analyzed 91 fMRI and PET studies of emotion, including 42 assessing fear ( Lindquist et al., 2012 ). The authors observed that, bilaterally, the amygdala was the most active brain region during fear perception paradigms (although not significantly more active during fear than other emotions), but that the amygdala was not preferentially active during fear experience paradigms. The selection of studies in this meta-analysis may account in part for the differential findings. For example, of the nine fear-experience studies included in this analysis, six were conducted by a group that uses primarily IAPS pictures ( Lang et al., 1999 ) and similar images to elicit disgust and fear (e.g., Stark et al., 2003 ; Schienle et al., 2005 ). These studies may be problematic because many of the “fear” images they use explicitly depict strong non-fear emotional cues (human or animal anger expressions) or depict events like a car accident or lava covering a road that are unpleasant but not obviously frightening. These meta-analyses also omitted pain anticipation and mood induction tasks included in other meta-analyses that are more directly relevant to fear experience ( Murphy et al., 2003 ; Vytal and Hamann, 2010 ). The third meta-analysis ( Sergerie et al., 2008 ) also excluded pain anticipation and mood induction tasks, in addition to employing a distinct analytical approach, whereby the authors compiled the statistical effect sizes of all studies of emotion (148 in total) that reported any activation in the amygdala and its surrounding regions. This approach yielded results showing amygdala activation that was stronger in response to positive emotional stimuli than to any negative emotional stimuli. Clearly, the conclusions drawn from the various meta-analyses are divergent enough to leave questions remaining as to whether the amygdala is in fact specifically implicated in fear responding.

Can the study of psychopathy clarify the role of the amygdala in fear experience? Perhaps, given the prominence of dysfunctional fear responding in psychopathy, empirical support that amygdala dysfunction underlies aberrant fear responding in psychopathic participants would support the amygdala's role in fear. And indeed, early hypotheses about the brain basis of psychopathy focused on potential amygdala dysfunction ( Patrick, 1994 ; Blair et al., 2001 ). More recently, the results of both functional and structural neuroimaging studies support these hypotheses. Several studies have observed that psychopathy is associated with reduced amygdala activation during the viewing of fearful emotional facial expressions but not other expressions like anger, a pattern that is independent of attentional processes ( Marsh et al., 2008 ; Dolan and Fullam, 2009 ; Jones et al., 2009 ; White et al., 2012 ). A recent study also found that psychopathy assessed in a community sample was also associated with a failure to exhibit amygdala activation to fear-evoking statements ( Marsh and Cardinale, 2012b ). Again, no group differences were observed in this task when other emotionally evocative statements were presented. (In addition, no main effect of fear stimuli was observed in the amygdala across groups. This suggests that amygdala responses to fear may fail to emerge in neuroimaging studies when the sample contains an unusual proportion of high psychopathy scorers.) Finally, a fear-conditioning paradigm found that psychopaths' failure to exhibit skin conductance responses during the task was accompanied by reduced activation in the amygdala and functionally connected regions of the cortex, such as orbitofrontal cortex and insula ( Birbaumer et al., 2005 ).

These patterns of dysfunction may stem from structural abnormalities in the amygdala, which have also been observed in psychopathy. Structural abnormalities across multiple nuclei in the amygdala have been observed in psychopathy ( Yang et al., 2009 , 2010 ; Ermer et al., 2012 ). Yang and colleagues observed not only significant bilateral volume reductions in the amygdalae of adult psychopaths relative to controls controls, but also surface deformations in the vicinity of the amygdala's basolateral, lateral, cortical, and central nuclei. A later study indicated that these deformities are more significant in “unsuccessful” psychopaths, or those who have been prosecuted for their criminal acts ( Yang et al., 2010 ). Ermer and colleagues identified gray matter reductions in adult psychopaths' amygdalae, in addition to other paralimbic regions such as parahippocampal gyrus ( Ermer et al., 2012 ). It should be noted that how specific nuclei of the amygdala are involved in psychopathy is not yet clear, in part due to insufficient spatial resolution of functional imaging scan. Various hypotheses have been proposed regarding the role of discrete nuclei in psychopathic symptoms ( Blair, 2005a ; Moul et al., 2012 ).

On the whole, the results of these studies directly link amygdala dysfunction to observed deficits in fear responding in psychopathy.

But perhaps the most compelling evidence that amygdala dysfunction underlies fear deficits in psychopathy emerges from the results of paradigms testing fear responding in psychopaths and individuals with lesions to the amygdala. As previously described, psychopathy has been found to impair anticipatory skin-conductance responses ( Lykken, 1957 ; Aniskiewicz, 1979 ; Herpertz et al., 2001 ; Birbaumer et al., 2005 ; Rothemund et al., 2012 ), fear-potentiated startle responses ( Levenston et al., 2000 ; Herpertz et al., 2001 ; Rothemund et al., 2012 ), aversive classical conditioning ( Flor et al., 2002 ), subjective experiences of fear ( Marsh et al., 2011 ) and the recognition of fear from the face, body and voice ( Marsh and Blair, 2008 ; Dawel et al., 2012 ). Striking parallels to these deficits can be found in studies of individuals with amygdala damage. In these individuals, comparable impairments in each of these fear paradigms have also been observed (Table 1 ).

Table 1. Comparison of deficits observed in samples with psychopathy and amygdala lesions .

Because amygdala dysfunction has been observed in psychopathy during several of these tasks, and because amygdala lesions impair performance in all of them, these patterns generate a compelling case for the role of the amygdala specifically in fear responding. Consistent with this, researchers studying one patient with bilateral amygdala damage (SM) clarify that she has not only striking deficits in fear responding, but these deficits are limited to fear responding:

SM's reaction to fear-inducing stimuli was not characterized by a loss of responsiveness, but rather manifested as a heightened arousal and interest in the face of a near-complete lack of avoidance and caution … Our findings suggest that the amygdala's role in the induction and experience of emotion is specific to fear. To say that SM is emotionless or unable to feel emotion is simply false. Her emotional deficit is primarily circumscribed to the behaviors and experiences that characterize a state of fear ( Feinstein et al., 2011 ).

The clear correspondence between patterns of fear dysfunction observed in psychopathy and following amygdala lesions, in the absence of other clear emotional deficits, provides strong support for the specific involvement of the amygdala in fear. Dysfunction in the amygdala, whether via acquired lesion or developmental psychopathology, impairs fear-related processes while leaving other forms of emotion, such as anger, positive excitement, and disgust, largely intact. In answer to our second question, then, research in psychopathy suggests that the amygdala—or, more likely, specific populations of neurons within the amygdala ( LeDoux, 2012 )—plays a critical role in generating fear but does not appear to be critical for other emotions like positive excitement and anger.

How do our own Experiences of Emotion Pertain to our Perceptions of and Responses to others' Emotion?

The findings reviewed thus far suggest answers to a third question of ongoing interest in psychology and neuroscience: how do our emotional experiences affect our responses to and perceptions of others' emotions?

As we have seen, the evidence is clear that psychopathy is associated with deficits in the experience of fear but not other emotions. Psychopathic individuals show reduced physiological responding during anticipation of an aversive event, are less apt to adapt their behavior in response to punishment, and report reduced subjective fear. In some psychopaths the experience of fear may be essentially absent but, in keeping with the idea that psychopathy is a continuum rather than a taxon, fear is likely muted to varying degrees rather than absent in most individuals with psychopathic traits. Finally, psychopathy impairs the recognition of others' fear. Three meta-analyses have now demonstrated that psychopathy impairs recognition of fearful facial expressions in the face, body, and voice ( Marsh and Blair, 2008 ; Wilson et al., 2011 ; Dawel et al., 2012 ), a pattern that is particularly closely associated with the central affective deficits of psychopathy. Marsh and Blair (2008) found that responses to fear are impaired to a significantly greater degree than any other emotion, and Dawel et al. (2012) found that the core affective features of psychopathy impaired the recognition of fear but not other emotions. In addition, psychopathy impairs the ability to identify the circumstances under which others would experience fear, such as in response to threats of harm ( Marsh and Cardinale, 2012a ). The parallels between psychopathic deficits in emotional experience and emotion recognition are striking. The emotion that psychopaths appear not to feel strongly—fear—is the same emotion that they have the most difficulty recognizing in others. Associations between the experience and recognition of emotion have previously been observed for a number of emotions, including fear ( Buchanan et al., 2010 ). These data suggest the possibility of a basic empathic failure in psychopaths—they have great difficulty understanding an emotion in others that they themselves do not feel (or at least, do not feel strongly). This breakdown appears to occur in primarily for fear, rendering others' expressions of fear essentially meaningless in individuals with psychopathic traits.

These patterns are consistent with the theory that we recognize others' emotions through a low-level empathic simulation process, exploiting our own experiences of an affective state to understand others' experiences ( Goldman and Sripada, 2005 ). Empathic simulation has become a favored explanation among researchers studying empathy for pain, boosted by a voluminous literature that the perception or inference of others' pain results in increased activation in the same brain structures involved in processing affective and motivational features of felt pain ( Lamm et al., 2011 ). It is now widely agreed that the experience of empathy for pain emerges from shared representations for personal and vicarious experiences of affective states ( Bernhardt and Singer, 2012 ).

The neurobiological evidence that empathy for fear also results from shared neural representations is equally compelling: both experienced fear and perceived fear result in specific activation in the amygdala, a structure that, when damaged or dysfunctional (as in the case of psychopathy), leads to impairments in both felt fear and the ability to recognize when others are experiencing fear. And yet an extremely similar pattern of data to support amygdala-based shared representations of fear has been interpreted differently from evidence supporting shared insula and anterior cingulate cortex-based representations for pain.

Why might this be? For one, the functions of the amygdala were first articulated in animal models, with a historical emphasis on stimulus-reinforcement learning rather than social functions and subjective experiences. This emphasis may have resulted in early observations of amygdala activity in response to fear expressions being interpreted as indicating that fear expressions signal threat, akin to the CS+ in a conditioning trial ( Breiter et al., 1996 ; Morris et al., 1996 ). However, there is little empirical data to support the idea that fear expressions are interpreted as primarily threatening. Indeed, fearful facial expressions have been shown to be more strongly appetitive than aversive ( Marsh et al., 2005b ), and to resemble the morphological appearance of an infantile face ( Marsh et al., 2005a ) consistent with the idea that others' fear elicits empathic concern. The assumption that fearful expressions signify threat because they elicit amygdala activation may be a case of erroneous reverse inference—an inference regarding the psychological significance of a stimulus on the basis of neural responses to it ( Poldrack, 2008 ).

Alternate hypotheses exist as well, such as that amygdala responses to fearful expressions reflect the amygdala's role in directing attention to the eyes of these expressions, which is critical to correctly identifying these stimuli ( Dadds et al., 2006 ; Han et al., 2012 ). This theory is supported by findings that instructing both patients with amygdala lesions and children with psychopathic traits to attend to the eyes of faces reduces fear recognition deficits ( Adolphs et al., 2005 ; Dadds et al., 2006 ). But this theory is less clearly able to accommodate the facts that psychopathy also impairs pre-attentive recognition of fearful faces ( Sylvers et al., 2011 ), that both amygdala lesions and psychopathy impair recognition of vocalized fear, auditory stimuli for which the relevance of attention directed to salient features is unclear ( Scott et al., 1997 ; Blair et al., 2002 ), and that psychopathy impairs the recognition of written statements that evoke fear ( Marsh and Cardinale, 2012a ). No low-level features of fear-evoking statements distinguish them from any other emotionally evocative statement, so there is no obvious mechanism by which the redirection of attention would be relevant to identifying these stimuli. I suggest that the total available evidence can be more parsimoniously interpreted under the hypothesis that amygdala is essential to generating an internal representation of fear, and that amygdala dysfunction in psychopathy impairs this process, thereby impairing identification of others' fear across contexts ( Marsh and Cardinale, 2012b ). This theory has the benefit of being consistent with the vast and consistent literature on empathy for pain.

That low-level emotional processes may impair empathy for fear in psychopathy may be particularly germane to an understanding of empathic processes more generally. “Empathy” is a term plagued by multiple overlapping definitions that include low-level emotional contagion, cognitive perspective-taking, and empathic concern ( de Waal, 2009 ). The form of empathy most notoriously impaired in psychopathy is empathic concern, sometimes called sympathy, the inverse of which is callousness ( Hare, 1991 ; Blair, 1995 ). By contrast, the evidence is clear that cognitive empathy, or perspective-taking, is not impaired in psychopathy ( Blair, 2008 ; Jones et al., 2010 ; Schwenck et al., 2012 ). But emotional contagion, defined as simple affectedness by another's emotional state ( de Waal, 2009 ), is clearly affected, at least in response to others' fear. The accumulated literature on psychopathy thereby suggests the possibility of critical links among emotional contagion in response to others' fear, recognition of others' fear, and empathic concern ( Nichols, 2001 ). It also reinforces the importance of resisting the temptation to conflate the various forms of empathy, which may rely on distinct neurobiological processes.

From a societal perspective, understanding empathic deficits for others' fear may be the most important question of all that the study of psychopathy helps to answer. Although amygdala lesion cases can illuminate the amygdala's role in fear, because these lesions usually occur in late adolescence or adulthood, their effects on the development of other brain regions and behavior is more limited. This may be why amygdala lesions in adulthood are not associated with heightened aggression, whereas the case of psychopathy suggests a strong relationship between developmental deficits in fear and aggression. Fear plays an important role in preventing or ending aggression during social encounters ( Blair, 1995 , 2005b ), and fearful emotional facial expressions elicit empathic concern and the desire to help from people who perceive them, even subliminally ( Marsh and Ambady, 2007 ). The rationale for much research on psychopathy is that individuals with this disorder are responsible for a disproportionate amount of suffering, as they engage in a variety of antisocial, criminal, and violent behaviors that cause others distress and fear ( Hare, 1993 ; Rutter, 2012 ). There is limited evidence that failure to exhibit empathic responses to others' pain is related to lower self-reported empathic concern or aggressive or antisocial behavior ( Singer et al., 2004 , 2006 ). In contrast, the evidence linking the failure to exhibit empathic responses to others' fear, both on a neural and a behavior level, is abundant. Psychopaths, in whom the failure to recognize others' fear or to generate empathic activation in the amygdala and autonomic nervous system is a hallmark feature, exhibit profound impairments in empathic concern for others and notoriously commit antisocial acts. Thus, as important as the study of psychopathy is for answering fundamental psychological and neuroscientific questions about the nature of emotion and empathy, an improved understanding of emotion and empathy as they pertain to psychopathy may be critical to developing improved means of ameliorating psychopaths' harmful effects on others.

Conclusions

The study of psychopathy has generated information relevant to addressing three questions of central importance to emotion and affective neuroscience. Evidence collected from psychopathic populations supports the conclusion that fear is qualitatively distinct from other emotions and arises from discrete neurobiological processes, rather than the conclusion that emotions like fear and anger reflect quantitative variations in core dimensions like arousal and valence. Recent neurocognitive and neuroimaging evidence also supports the specific role of the amygdala in generating a fear response over the view that the amygdala plays a domain-general role equally relevant to the generation of multiple emotions. And finally, psychopaths' parallel deficits in experiencing fear and recognizing fear in others lend support to the notion that empathy for affective states results from shared representations for personal and vicarious experiences of fear, consistent with simulation-based theories of empathy. These conclusions may prove useful not only in furthering the neuroscientific studies of emotion, but in developing a better understanding of the fundamental nature of psychopathy, empathy and aggression.

Conflict of Interest Statement

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Keywords: psychopathy, emotion, amygdala, empathy, fear

Citation: Marsh AA (2013) What can we learn about emotion by studying psychopathy? Front. Hum. Neurosci . 7 :181. doi: 10.3389/fnhum.2013.00181

Received: 08 February 2013; Paper pending published: 01 March 2013; Accepted: 22 April 2013; Published online: 10 May 2013.

Reviewed by:

Copyright © 2013 Marsh. This is an open-access article distributed under the terms of the Creative Commons Attribution License , which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.

*Correspondence: Abigail A. Marsh, Department of Psychology, Georgetown University, 37 th and O Streets NW, WGR 302A, Washington, DC 20057, USA. e-mail: [email protected]

This article is part of the Research Topic

What determines social behavior? Investigating the role of emotions, self-centered motives, and social norms.

Treating the untreatable: a single case study of a psychopathic inpatient treated with schema therapy

Affiliations.

• 1 Department of Clinical Psychological Science.
• 2 Forensic Psychiatric Centre de Rooyse Wissel.
• PMID: 24684220
• DOI: 10.1037/a0035773

From its first conceptualization in modern psychiatry, psychopathy has been considered difficult if not impossible to treat. Schema Therapy (ST) is a psychotherapeutic approach that has shown efficacy in patients with borderline personality disorder. ST has recently been adapted for personality disordered forensic patients, including patients with high levels of psychopathy. The present case study examined the process of individual ST, combined with movement therapy and milieu therapy by the nursing staff, with a forensic inpatient with psychopathic features (Psychopathy Checklist-Revised total score = 28.4). The patient had been sentenced to a mandatory treatment order in relation to a sexual assault. We assessed change using independent assessments of psychopathic traits, cognitive schemas, and risk-related behaviors over the 4-year treatment period and a 3-year follow-up. We also assessed the quality of the working alliance. Reliable change analyses showed significant improvements in psychopathic traits, cognitive schemas, and risk-related outcomes. At 3 years posttreatment, the patient was living independently outside of the forensic institution without judicial supervision and he had not reoffended. While many questions remain about the effectiveness of psychotherapeutic treatment for psychopathic patients, our study challenges the view that they are untreatable.

PsycINFO Database Record (c) 2014 APA, all rights reserved.

Publication types

• Case Reports
• Aggression / psychology
• Antisocial Personality Disorder / therapy*
• Criminal Psychology / methods
• Evidence-Based Medicine / methods
• Follow-Up Studies
• Hospitals, Psychiatric
• Inpatients / psychology*
• Netherlands
• Prisoners / psychology
• Professional-Patient Relations*
• Psychotherapy / methods*
• Sex Offenses / psychology*
• Treatment Outcome

The Psychopathic Patient - A Case Study

Therapy session notes provide insight into living with Antisocial Personality Disorder (AsPD) - psychopaths and sociopaths.

• Watch the video on A Psychotherapist and the Psychopath  

Notes of first therapy session with Ani Korban, male, 46, diagnosed with Antisocial Personality Disorder (AsPD), or Psychopathy and Sociopathy

Ani was referred to therapy by the court, as part of a rehabilitation program. He is serving time in prison, having been convicted of grand fraud. The scam perpetrated by him involved hundreds of retired men and women in a dozen states over a period of three years. All his victims lost their life savings and suffered grievous and life-threatening stress symptoms.

He seems rather peeved at having to attend the sessions but tries to hide his displeasure by claiming to be eager to "heal, reform himself and get reintegrated into normative society". When I ask him how does he feel about the fact that three of his victims died of heart attacks as a direct result of his misdeeds, he barely suppresses an urge to laugh out loud and then denies any responsibility: his "clients" were adults who knew what they were doing and had the deal he was working on gone well, they would all have become "filthy rich." He then goes on the attack: aren't psychiatrists supposed to be impartial? He complains that I sound exactly like the "vicious and self-promoting low-brow" prosecutor at his trial.

He looks completely puzzled and disdainful when I ask him why he did what he did. "For the money, of course" - he blurts out impatiently and then recomposes himself: "Had this panned out, these guys would have had a great retirement, far better than their meager and laughable pensions could provide." Can he describe his typical "customer"? Of course he can - he is nothing if not thorough. He provides me with a litany of detailed demographics. No, I say - I am interested to know about their wishes, hopes, needs, fears, backgrounds, families, emotions. He is stumped for a moment: "Why would I want to know these data? It's not like I was their bloody grandson, or something!"

Ani is contemptuous towards the "meek and weak". Life is hostile, one long cruel battle, no holds barred. Only the fittest survive. Is he one of the fittest? He shows signs of unease and contrition but soon I find out that he merely regrets having been caught. It depresses him to face incontrovertible proof that he is not as intellectually superior to others as he had always believed himself to be.

Is he a man of his word? Yes, but sometimes circumstances conspire to prevent one from fulfilling one's obligations. Is he referring to moral or to contractual obligations? Contracts he believes in because they represent a confluence of the self-interests of the contracting parties. Morality is another thing altogether: it was invented by the strong to emasculate and enslave the masses. So, is he immoral by choice? Not immoral, he grins, just amoral.

How does he choose his business partners? They have to be alert, super-intelligent, willing to take risks, inventive, and well-connected. "Under different circumstance, you and I would have been a great team" - he promises me as I, his psychiatrist, am definitely "one of the most astute and erudite persons he has ever met." I thank him and he immediately asks for a favor: could I recommend to the prison authorities to allow him to have free access to the public pay phone? He can't run his businesses with a single daily time-limited call and this is "adversely affecting the lives and investments of many poor people." When I decline to do his bidding, he sulks, clearly consumed by barely suppressed rage.

How is he adapting to being incarcerated? He is not because there is no need to. He is going to win his appeal. The case against him was flimsy, tainted, and dubious. What if he fails? He doesn't believe in "premature planning". "One day at a time is my motto." - he says smugly - "The world is so unpredictable that it is by far better to improvise."

He seems disappointed with our first session. When I ask him what his expectations were, he shrugs: "Frankly, doctor, talking about scams, I don't believe in this psycho-babble of yours. But I was hoping to be able finally communicate my needs and wishes to someone who would appreciate them and lend me a hand here." His greatest need, I suggest, is to accept and admit that he erred and to feel remorse. This strikes him as very funny and the encounter ends as it had begun: with him deriding his victims.

This article appears in my book, "Malignant Self Love - Narcissism Revisited"

next: The Narcissistic Patient ~ back t o: Case Studies: Table of Contents

APA Reference Vaknin, S. (2009, October 1). The Psychopathic Patient - A Case Study, HealthyPlace. Retrieved on 2024, April 16 from https://www.healthyplace.com/personality-disorders/malignant-self-love/psychopathic-patient-a-case-study

Medically reviewed by Harry Croft, MD

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A STUDY OF 50 CASES OF PSYCHOPATHIC PERSONALITY

• G. E. Partridge

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• Personality Disorders and Criminal Behavior
• Child Maltreatment and Psychopathy 16 November 2020
• Psychopathy in Italian female murderers 24 November 2019 | Behavioral Sciences & the Law, Vol. 37, No. 5
• Psychopathy, Its Etiology, and the Nature of Crime 16 September 2016
• The emergence and development of psychopathy 22 July 2014 | History of the Human Sciences, Vol. 27, No. 5
• Introduction 23 March 2012
• International Journal of Forensic Mental Health, Vol. 11, No. 4
• Early Environmental Predictors of the Affective and Interpersonal Constructs of Psychopathy 24 December 2008 | International Journal of Offender Therapy and Comparative Criminology, Vol. 54, No. 1
• Development and Psychopathology, Vol. 21, No. 3
• References 13 January 2010
• Psychopathy and therapeutic pessimism Clinical Psychology Review, Vol. 22, No. 1
• American Psychiatrists and the Modern Man, 1900 to 1920 24 July 2016 | Men and Masculinities, Vol. 1, No. 1
• Psychopathy and violent behaviour in abused and neglected young adults 10 March 2006 | Criminal Behaviour and Mental Health, Vol. 6, No. 3
• HEREDITY AND CRIME: BAD GENES OR BAD RESEARCH?* 7 March 2006 | Criminology, Vol. 27, No. 3
• DANIEL S. HELLMAN , and
• NATHAN BLACKMAN
• SIDNEY MALITZ
• PATRICIA O'NEAL ,
• LEE N. ROBINS ,
• LUCY JANE KING , and
• JEANETTE SCHAEFER
• The Psychiatric Quarterly, Vol. 11, No. 1

Psychopathy

The truth about corporate psychopaths, what research does—and does not say about psychopathy in the office..

Posted May 12, 2023 | Reviewed by Tyler Woods

• What Is a Career
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• The media has been propagating a narrative about a shocking proportion of psychopaths in corporations.
• This narrative is generally based on popular books and practitioner opinions, rather than on scientific research.
• Yet the academic community played its own part in feeding the media frenzy: they devised a branding solution.
• To compensate for the lack of studies in corporations, psychopathy in any workplace (even SMEs or NGOs) was branded “corporate psychopathy”.

The rise of the "corporate psychopath"

“One in five corporate CEOs is a psychopath. Wait, it’s not CEOs but managers and it’s not corporations but organizations of any size. In fact, it’s not one in five but one in eight. Okay, there’s no conclusive evidence of corporations teeming with psychopaths. But we all know they do.”

The above is a synopsis of what could be called The Great Corporate Psychopath Frenzy, a media phenomenon that emerged around the turn of the millennium and is still going strong. It picked up in intensity in 2016, stirred by an Australian study finding that one in five business employees could be a psychopath. Numerous top business media outlets rushed to cover the news. With a flick of the pen, they converted “business employees” into “CEOs” in breathless titles such as “21 percent of CEOs are psychopaths. Only 21 percent?” (Washington Post). Some added “American Psycho” axe-wielding pictures for good measure. Two years later, the source research study was retracted (a rare occurrence in academia, indicating serious credibility shortcomings) but the titles stayed, a “scientific fact” you might have heard repeated at a party or two.

Academics join the party

Sensing the media value of associating the words “psychopath” and “corporation”, some academics joined the party, by taking research findings related to psychopathy at any workplace and branding them “corporate psychopathy”. This is not unlike prefacing “ narcissism ” with “artistic” since, well, some narcissists are artists, and the term makes for more vivid imagery than “narcissism” alone.

Of the more than 40 empirical papers on “corporate psychopaths” published in scientific journals, the vast majority study employees or managers who do not work in corporations, but in non-profit organizations, civil service institutions, or small companies. A title such as “A case study of a corporate psychopath CEO”, might evoke the image of a magnate frowning at Manhattan from his sky-high office while pensively sharpening the blade of an axe. Instead, the paper with the said title reports on the head of a British charity (Boddy, 2017). How about “Corporate psychopaths, conflict, and employee well-being”? It does not bring to mind your local car repair shop or family restaurant, does it? Yet half of the respondents in the above-mentioned study worked for companies with fewer than 50 employees. This did not stop the authors from presenting their study as an investigation into “those psychopaths working in the corporate sector, possibly attracted by the high monetary rewards, prestige and power available to those who reach the senior managerial levels of large corporations” (Boddy, 2014, page 108).

Voices of reason

Scientific reviews of the state of research on the topic of psychopathy in the workplace have repeatedly attempted to put things into proportion. A 2013 review co-authored by Scott Lilienfeld, the co-creator of one of the most widely used psychopathy measures, the Psychopathic Personality Inventory (PPI-R), dryly noted that “the attention given to psychopathy in the workplace by the media and scholars alike has greatly outstripped the scientific evidence” (Smith & Lilienfeld 2013, page 205). More recently, a 2019 review of all research studies on psychopathy and leadership concluded that “concern over psychopathic tendencies in organizational leaders may be overblown” (Landay, Harms, & Crede, 2019, page 183). The lead author of the above review got to experience this firsthand: a journalist cited her saying “there is no conclusive evidence indicating that a large percentage of CEOs are psychopaths”, but then, without producing any other research evidence, still concluded that “ roughly 4% to 12% of CEOs exhibit psychopathic traits , according to some experts”.

Psychopathy does not make you a psychopath

Psychopathy involves being fearless, impulsive and rebellious, not troubled by anxiety nor by feelings for others. It also includes being aggressive, ready to assign blame to anyone but oneself, yet also able to manipulate and influence others (Benning et al., 2003). Everyone has some level of psychopathy, but only those who score highest on the traits above (roughly 1 percent of the general population ), can be called psychopaths.

Of young men, Europeans and surgeons

Men across the globe are two to three times more likely to score higher than women on psychopathy (Neumann et al., 2012), and younger adults score distinctly higher on psychopathy than do older adults (Lilienfeld et al., 2014). Yet we don’t think of “A Clockwork Orange” every time we cross a young man in the street.

Europeans are more “psychopathic” than North Americans (Neumann et al., 2012), but this doesn’t seem to rank high in American tourists’ concerns when booking their Paris holidays. And, although surgeons in training have significantly higher psychopathy scores than do other medical students (Muscatello et al., 2017), I would certainly not forgo general anaesthesia to keep an eye on the surgeon’s scalpel... even if the surgeon is young, male and European.

Why getting the record straight on "corporate psychopaths" is important

This is not to say that bosses’ subclinical levels of psychopathy are irrelevant. As you would expect, psychopathic tendencies in managers correlate with employee dissatisfaction, turnover intentions, and bullying , although, surprisingly, the correlation is not very strong (Landay et al, 2019). However, when examined at these subclinical levels, focusing on leader psychopathy alone adds little explanatory power over toxic leader personalities that have been well studied (Smith & Lilienfeld, 2013) but much scare power when such findings are popularized for a general audience.

Why is it important, outside of academic circles, to set the record straight on “corporate psychopaths”?

First because, intimidated by media outcries about corporations teeming with psychopaths, many young people in search of a job may choose to stay away from corporations altogether, potentially forfeiting a better career path than may otherwise be available to them. And who is most susceptible to be harmed by such misinformation? Those who are already underprivileged, as they are less likely to have friends or relatives in corporations who could give them first-hand reassurance.

Second, current corporate employees may give up on their boss at the first sign of egocentricity, impulsivity, or lack of empathy. This can have many negative consequences for the employee, the boss, and the organization. For example, would you dare give feedback to your manager about their tin-eared reaction to a colleague’s emotional distress if you thought they might axe you for it, whether literally or metaphorically? Yet feedback is essential for personal and organizational learning: as this blog’s motto reminds us, most managers are not perfect, and most managers can improve. Even if you’ve chanced upon a boss from hell, knowing that they are very unlikely to be clinical psychopaths would make you feel safer in looking for ways to get them brought to justice, from a scathing 360 degree review to whistleblowing, to filing a complaint with HR, to using other tools and rules that, ironically, corporations may be better at providing than most other, less structured organizations.

Make no mistake about it: corporations have much to improve. But focusing on the overblown menace of “corporate psychopaths” distracts effort and attention from weeding out toxic executives as well as from helping regular humans working in corporations to become better leaders—and better followers.

Benning, S. D., Patrick, C. J., Hicks, B. M., Blonigen, D. M., & Krueger, R. F. (2003). Factor structure of the psychopathic personality inventory: Validity and implications for clinical assessment. Psychological Assessment, 15 (3), 340-350.

Boddy, C. R. (2014). Corporate Psychopaths, Conflict, Employee Affective Well-Being and Counterproductive Work Behaviour. Journal of Business Ethics, 121 (1), 107-121.

Boddy, C. R. (2017). Psychopathic Leadership. A Case Study of a Corporate Psychopath CEO. Journal of Business Ethics, 145 (1), 141-156.

Landay, K., Harms, P. D., & Crede, M. (2019). Shall We Serve the Dark Lords? A Meta-Analytic Review of Psychopathy and Leadership. Journal of Applied Psychology, 104 (1), 183-196.

Lilienfeld, S. O., Latzman, R. D., Watts, A. L., Smith, S. F., & Dutton, K. (2014). Correlates of psychopathic personality traits in everyday life: results from a large community survey. Frontiers in Psychology, 5 .

Muscatello, M. R. A., Bruno, A., Genovese, G., Gallo, G., Zoccali, R. A., & Battaglia, F. (2017). Personality Traits Predict a Medical Student Preference to Pursue a Career in Surgery. Education for Health, 30 (3), 211-214.

Neumann, C. S., Schmitt, D. S., Carter, R., Embley, I., & Hare, R. D. (2012). Psychopathic Traits in Females and Males across the Globe. Behavioral Sciences & the Law, 30 (5), 557-574.

Smith, S. F., & Lilienfeld, S. O. (2013). Psychopathy in the workplace: The knowns and unknowns. Aggression and Violent Behavior, 18 (2), 204-218.

Emilia Bunea, Ph.D. , is a leadership researcher and educator, as well as the CEO of Ed.movie Inc., a California-based edutainment company. She previously held a series of CFO and CEO roles in global financial organizations.

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Case study, a term which some of you may know from the "Case Study of Vanitas" anime and manga, is a thorough examination of a particular subject, such as a person, group, location, occasion, establishment, phenomena, etc. They are most frequently utilized in research of business, medicine, education and social behaviour. There are a different types of case studies that researchers might use:

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Prevalence of Psychopathy in the General Adult Population: A Systematic Review and Meta-Analysis

Associated data.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The main objective of this study was to systematically and meta-analytically review the scientific literature on the prevalence of psychopathy in the general adult population. A search in PsycInfo, MEDLINE, and PSICODOC identified 15 studies published as of June 2021. Altogether, 16 samples of adults totaling 11,497 people were evaluated. Joint prevalence rates were calculated using reverse variance heterogeneity models. Meta-regression analyses were conducted to examine whether the type of instrument, sex, type of sample, and country influenced prevalence. The meta-analytical results obtained allow us to estimate the prevalence rate of psychopathy in the general adult population at 4.5%. That being said, this rate varies depending on the participants' sex (higher in males), the type of sample from the general population (higher in samples from organizations than in community samples or university students), and the type of instrument used to define psychopathy. In fact, using the PCL-R, which is currently considered the “gold standard” for the assessment and definition of psychopathy, the prevalence is only 1.2%. These results are discussed in the context of the different theoretical perspectives and the existing problems when it comes to defining the construct of psychopathy.

Introduction

The construct of psychopathy is understood generically as a type of personality disorder characterized, among other important features, by the presence of behaviors that conflict with the social, moral, or legal norms of society, giving rise in many cases to clearly criminal behaviors (Hare, 2003a , b ; Crego and Widiger, 2018 ; Lykken, 2018 ; Patrick, 2018 ; Widiger and Crego, 2018 ). This construct is widespread in the area of psychopathology or personality psychology, but above all, in the area of legal and forensic psychology, including criminal and prison psychology. In fact, for some researchers, such as Hare ( 1998 ), psychopathy is one of the most important clinical constructs in these areas. This is because the personality and behavior of offenders with a diagnosis of psychopathy are very different from those of other offenders. Furthermore, according to Hare ( 1998 ), those differences are not only as important as environmental, social, and situational factors to understand crime, but they also allow us to improve the assessment of the risk of recidivism and violence and select appropriate treatment programs.

However, the concept of psychopathy has evolved throughout history and in this evolution, perhaps a key moment for the objectives of the present work is the proposal made by Hervey Cleckley in the 1940s (Cleckley, 1988 ). Cleckley proposed a very clear distinction between the criminals and the person suffering from psychopathy. What fundamentally defines psychopathy is not criminal behavior, but the presence of a series of personality traits, generally related to a lack of emotion (e.g., lack of nervousness, absence of remorse or shame, inability to love, shallow affective reactions) and the presence of an outward appearance of normality (e.g., lack of delusions and other signs of irrational thought, superficial charm, and good “intelligence”). Therefore, for Cleckley, not all criminals are psychopaths, and not all psychopaths are criminals. Hence, there would be people in the general population who would have a psychopathic personality, but who would never have committed any crime and will perhaps never commit one. However, they will manifest socially maladaptive and ethically reprehensible behaviors (e.g., failure to follow a life plan, impersonal, trivial, and poorly integrated sex life, deceitfulness and lack of sincerity, pathological egocentrism).

As he (Hare, 2013 ) acknowledged, Cleckley's conception of psychopathy greatly influenced the work of Robert Hare's. Hare has become one of the highest authorities in the field of psychopathy, especially since the elaboration and publication in 1991 of the Hare Psychopathy Checklist-Revised or PCL-R (Hare, 1991 ). The PCL-R has, over the years, become the “gold standard” for the evaluation of psychopathy in forensic and prison contexts (Edens et al., 2001 ).

The PCL-R is a symptom construct rating scale of 20 items that, using a semi-structured interview and data from the case files and other collateral information, provides a score in psychopathy that can range from 0 to 40. The cut-off score of 30 (30 or more) is the most used to classify a person as a psychopath. However, some research has used a cut-off score of 25 to identify subclinical psychopathy, which already indicates a high level of psychopathy (Hare, 2013 ).

The items of the PCL-R are intended to cover most of Cleckley's characteristics of psychopathy. However, as the instrument was developed and validated in the prison population, the concept of psychopathy underlying the PCL-R attaches more weight to the characteristics of criminality and a socially deviated lifestyle than Cleckley's original conception. This difference is reflected in PCL-R items such as juvenile delinquency, parole revocation, and criminal versatility (Items 18, 19, and 20, respectively).

The application and scoring of the PCL-R requires a lot of time and involves access to information from files and collateral sources. Therefore, in 1995, an abbreviated version was developed for its use in screening task: the Hare Psychopathy Checklist-Screening Version or PCL:SV (Hart et al., 1995 ). This version has only 12 items and does not require consultation of other sources of information. When using the PCL:SV in forensic and prison population, it is common to use a cut-off score of 18 (or more) to identify psychopathy and a cut-off score of 13 (or more) to identify subclinical psychopathy.

Drawing on the PCL-R and its different versions, including the PCL:SV, the scientific literature on psychopathy in the forensic or prison population has grown dramatically in the last 30 years. Hence, there are currently many correlational studies, but also experimental or laboratory studies that have addressed very different aspects of this construct in this type of population. These aspects are its structure, etiology, psychological mechanisms and psychobiological correlations to its relationship with a wide variety of factors (e.g., sex, age, socioeconomic status, education, family environment, ethnicity, culture). Also, its ability to predict diverse socially or clinically relevant behaviors (e.g., violence, criminal recidivism, gender-based violence, sexual offending, institutional misconduct, alcohol and substance abuse, response to treatment) (see reviews of Leistico et al., 2008 ; Hare, 2013 ; Fox and DeLisi, 2019 ).

The results of some of these investigations that have examined differences in psychopathy based on sex or culture are particularly relevant to the aims of this study. Research has consistently found that the prevalence of psychopathy is higher in male offenders and prisoners than in female offenders and prisoners (see the review of Beryl et al., 2014 ). It has also been found that psychopathy prevalence and psychopathy levels are higher in North American male and female prisoners than in European male and female prisoners (see the reviews of Beryl et al., 2014 ; Fox and DeLisi, 2019 ).

Despite all the data that support the validity and usefulness of the psychopathy construct, a source of controversy concerning it has to do with the possibility of considering it as a categorical or a dimensional construct. A categorical classification allows a clear differentiation between people who have psychopathy and people who don't, because there would be qualitative differences between them. In contrast, if it is considered as a dimensional construct and therefore, a maladaptive variant of the normal personality, there would only be quantitative differences between such persons.

The latter possibility is supported by a growing scientific literature concerning at least four major lines of research and argumentation: (1) the relationship between psychopathy and the five-factor personality model, also known as the Big Five model, and which is currently considered the most validated and consensual model of personality traits (e.g., Widiger and Lynam, 1998 ; Deferinko and Lynam, 2013 ; Vachon et al., 2013 ; Lynam and Miller, 2019 ); (2) the relationships between the PCL-R and other instruments specifically designed to measure psychopathic personality traits in normal population (e.g., Sellbom et al., 2018 ; Sleep et al., 2019 ); (3) the relationship between the constructs that make up the nomological network of psychopathy (e.g., violence, criminality, antisocial behavior, alcohol abuse, etc.) and the five-factor model or instruments that measure psychopathic personality traits in normal population (e.g., Watt and Brooks, 2012 ; Vize et al., 2018 ; Sleep et al., 2019 ); and (4) studies that have examined through taxonomic methodology whether psychopathy is a dimensional or a categorical construct (e.g., Guay et al., 2007 , 2018 ).

Reviewing all these lines of research is beyond the scope of this work, but, in general, the data of all of them seem to support a dimensional view of psychopathy, which conceives it as a maladaptive variant of the normal personality. As a result, in recent years, there is strong interest in studying the presence and influence of psychopathy in everyday life, from the working world to couple relationships (Hare, 2003b ; Dutton, 2012 ; Babiak and Hare, 2019 ; Fritzon et al., 2020 ). The scientific literature acknowledges the existence of people with high levels of psychopathy who are not offenders or violent, the so-called “integrated psychopaths.” It also acknowledges the existence of people with high levels of psychopathy who achieve great success in their lives, the so-called “successful psychopaths.” The construct of “successful psychopathy” refers to those psychopathic personality traits such as lack of fear, high self-confidence or charisma, which can be beneficial in certain contexts (Dutton, 2012 ; Lilienfeld et al., 2015 ).

In this direction, it has been proposed that it would be possible to find higher levels of psychopathic traits in certain professions or occupations (e.g., entrepreneurs, managers, politicians, investors, salesmen, surgeons, lawyers, telemarketing employees). The reason behind this could be that it is precisely these traits the ones that could boost the tasks involved in those professions or occupations and even facilitate success in them (Hare, 2003b ; Dutton, 2012 ; Babiak and Hare, 2019 ; Fritzon et al., 2020 ). Among these professions, some are typically related to office workers, the so-called “white-collar workers;” hence, the term “white-collar psychopathy” has been coined, although the term “corporate psychopathy” or “organizational psychopathy” is also used.

In this regard, Dutton ( 2012 ), after applying the Levenson Self-Report Psychopathy Scale (LSRP; Levenson et al., 1995 ) online to 5,400 people and asking about their profession, found that, in the United Kingdom, the 10 professions with the highest levels of psychopathic traits were company CEOs, lawyers, radio or television characters, salespersons, surgeons, journalists, priests, police officers, chefs, and civil servants. On the other hand, the 10 professions with the lowest levels of psychopathic traits were social-health assistants, nurses, therapists, artisans, stylists, charity workers, teachers, creative artists, physicians, and accountants. In the same direction, Lilienfeld et al. ( 2014 ) applied the brief version of the Psychopathic Personality Inventory-Revised (PPI-R-SF; Lilienfeld and Widows, 2005 ), obtaining valid responses from 3,388 people. What they found was that people in a managerial position at work had higher levels of psychopathic traits than those who did not occupy such positions, and that those who worked in jobs with occupational risk (e.g., police officers, firefighters, military service people, miners) also had higher levels of psychopathic traits than those working in jobs without occupational risk. Employers also showed higher levels of psychopathic traits compared to psychologists and other mental health professionals.

In this theoretical and empirical context, the main objective of this work was to systematically review the scientific literature on the prevalence of psychopathy in the general population. By doing so, we have obtained an estimate of its prevalence rate in that population because, to our knowledge, no studies have reviewed that scientific literature to date. In this sense, this work hypothesizes that this prevalence will be much lower than the one observed in the offender or prison population. Secondarily, the present work was intended to examine the influence of the following factors on the prevalence of psychopathy in the general population: the type of instrument used to evaluate and define psychopathy, people's sex, their profession-occupation, and their country of origin. In this line, and based on the scientific literature presented above, this work hypothesizes that the prevalence rates will be lower using the PCL-R (or any of its versions) than with other instruments; they will be higher in males than in females; higher in samples of employees and managers of certain commercial or financial organizations or companies than in other types of samples obtained from the general population; and higher among people from North American countries than in people from European countries.

The present review was focused on the prevalence of psychopathy as defined by the authors of the reviewed studies, but it did not examine the prevalence of psychopathic personality traits. Therefore, and as it will be explained in more detail later, studies about the prevalence of psychopathic personality traits or psychopathic facets (e.g., meanness, disinhibition, fearless dominance, psychopathic interpersonal facet) that did not define the presence of psychopathy based on those traits or facets were excluded from the review.

Identification of Publications

To find studies relevant to the objectives of this work, on June 20, 2021, a bibliographic search was carried out in PsycInfo, MEDLINE, and PSICODOC. These are currently the most complete bibliographic databases in psychology, medicine, and psychology in Spanish, respectively. The search was performed in PsycInfo and MEDLINE using the following words in any field of the databases: community or university or college or normal or non-criminal , combined with these three terms in the summary or document title fields: prevalence and psychopathy or psychopathic trait . When conducting the search in PsycInfo and MEDLINE, the following expression was specifically used: (ab((psychopathy or “psychopathic trait”) and prevalence) or ti((psychopathy or “psychopathic trait”) and prevalence)) and (community or university or college or normal or non-criminal) . The search in PSICODOC was performed by combining the following pairs of words (in Spanish) in any field of the database: prevalence and psychopathy or prevalence and psychopath or prevalence and psychopathic . In particular, the following expression was used in the PSICODOC search: (prevalence and psychopathy) or (prevalence and psychopath) or (prevalence and psychopathic) .

Previous searches identified 157 publications. After discarding duplicates that appeared in two or more bibliographic databases and adding six different publications identified after consulting the literature cited in the consulted studies, 147 publications were obtained. Figure 1 presents a summary using the flowchart proposed by the PRISMA group for the publication of systematic reviews of the scientific literature (Moher et al., 2009 ). It also shows the process followed for the search, screening, and selection of studies on the prevalence of psychopathy in the general adult population.

Flowchart of the process of searching and selecting studies on the prevalence of psychopathy in the general adult population.

Screening of Publications

Based on the objectives of this work and the reading of the titles, basic bibliographic data, and abstracts, the 147 publications initially found were screened to determine whether they met the following inclusion criteria: (1) it reports an empirical study that provides data on the prevalence of psychopathy; (2) it reports a study carried out with samples of adult participants from the general population, including community samples, organizations or companies, university students, private professions, etc., but not clinical samples or samples from forensic or prison contexts; (3) it describes the procedure used to define and evaluate psychopathy; and (4) it is a journal article, book, or book chapter. Doctoral dissertations, master's theses, and technical reports were excluded because of the difficulties sometimes encountered to achieve their full text. Presentations at congresses were also excluded because of the limited information on the studies they usually present.

Therefore, as shown in Figure 1 , publications reporting theoretical studies or literature reviews (34 publications) were excluded. Three publications that reviewed other works (book reviews) or submitted commentaries on other studies were also excluded. Publications reporting single-case studies (one publication) or reporting studies of samples of participants from the forensic population (34 publications), samples of patients with psychological or physical disorders (10 publications), samples of children or adolescents (13 publications), or animal samples (one publication) were also excluded. Finally, 11 publications that were doctoral dissertations or master's theses were excluded. Following these exclusions, the sample of publications was reduced to 40.

Study Eligibility

Of the 40 publications resulting from the screening phase, their full text was obtained, and, based on their reading, these publications were re-evaluated for compliance with the inclusion criteria. As reflected in Figure 1 , 23 publications were excluded at this stage because, although they reported empirical studies of samples of adult participants from the general population, they did not provide data on the prevalence of psychopathy in these samples. Some of these publications reported empirical studies on the prevalence of some psychopathic personality traits or psychopathic facets, but, since they did not define the presence of psychopathy based on those traits or facets, they were excluded from the review. For example, Neumann et al. ( 2012 ) calculated the proportion of adults from the general population across sex and world region that showed a high level for each facet of the Self-Report Psychopathy Scale (SRP) of Hare: interpersonal, affective, lifestyle, and antisocial. However, Neumann et al. ( 2012 ) did not define psychopathy based on SRP facets. For example, they did not establish if it is necessary to show high levels in all four SRP facets to identify psychopathy, or if it is necessary to show high levels in only three, two or one of the four facets. It is also not indicated if it is necessary to show a high level in a particular facet—e.g., antisocial—in addition to high level in one or two of the remaining facets. Therefore, Neumann et al. ( 2012 ) did not report data on the prevalence of psychopathy and their study was excluded from the present review.

Finally, two more publications were excluded. One of these publications offered data on the prevalence of antisocial personality disorder, but not the prevalence of psychopathy. The second publication reported a study conducted with the same sample of adults from the general population who participated in a previously published study. Given that it offered the same psychopathy prevalence data as that prior study, it was also excluded.

Studies Included in the Review

Following the screening and eligibility process of the initially identified publications, this systematic review finally included 15 publications reporting 15 studies. The main characteristics of these studies in terms of their participants and the definition of psychopathy used are summarized in Table 1 .

Main characteristics of studies on the prevalence of psychopathy in the general adult population analyzed in this systematic review.

Note: LSRP, Levenson Self-Report Psychopathy Scale (Levenson et al., 1995 ); PCL-R, Hare Psychopathy Checklist-Revised (Hare, 1991 , 2003a ); PCL:SV, Hare Psychopathy Checklist-Screening Version (Hart et al., 1995 ); PPI, Psychopathic Personality Inventory (Lilienfeld and Andrews, 1996 ); PPI-R, Psychopathic Personality Inventory-Revised (Lilienfeld and Widows, 2005 ); PPTS, Psychopathic Personality Traits Scale (Boduszek et al., 2016 ); SRP-II, Self-Report Psychopathy Scale-II (Hare, 1990 ); SRP-III, Self-Report Psychopathy Scale-III (Paulhus et al., 2016 ) .

Statistical Analysis

The meta-analytical calculations to estimate the joint prevalence of psychopathy and the heterogeneity and bias indices of the results were performed using MetaXLversion 5.3 (EpiGear International, Sunrise Beach, QLD, Australia), whereas the meta-regression analyses were performed with Stata, version 15 (Stata Corp, College Station, TX, USA) based on the data provided by MetaXL.

To stabilize the variances, the double arcsine transformation of the prevalences was used to calculate the conjoint prevalence, and an inverse variance heterogeneity model was used, as this model uses robust error variances (Barendregt et al., 2013 ; Wang and Liu, 2016 ). A random-effects model was also used but, as its results were virtually the same, they are not presented in this article for the sake of brevity. To facilitate the interpretation of the results, individual and joint prevalences are presented in the graphs as proportions after reversing the applied transformations. To assess the heterogeneity between the studies, Cochran's Q test and the I 2 statistic were calculated, and to evaluate the publication biases of the meta-analysis, we used the Doi chart and the Luis Furuya-Kanamori index (LFK), which has been shown to be better than the plot funnel and Egger's linear regression test for skewness detection and, hence, publication biases (Furuya-Kanamori et al., 2018 ).

The combined prevalences for different subgroups of studies created based on the following moderator variables were also calculated, following the above methods: type of instrument used to measure psychopathy (PCL-R vs. other instruments), participants' sex (male vs. female), type of samples of the general population (organizations vs. community vs. university students), and country of origin of the samples (North America vs. United Kingdom-Australia vs. mainland Europe). The significance of the differences in the joint prevalences of the different subgroups was tested with individual meta-regression analyses for each of these moderator variables and through a multiple meta-regression analysis with all the moderator variables that were statistically significant in individual analyses. In the case of the two moderator variables with three categories (sample type and country), two binary dummy variables were created for each of them for the meta-regression analyses.

Characteristics of the Studies

A total of 16 unique samples of participants from 15 studies were used to estimate the prevalence of psychopathy in the general adult population because, in one of the studies listed in Table 1 (Boduszek et al., 2021 ), a sample of adults from the population and another sample of university students participated, obtaining differentiated psychopathy prevalence rates for each of these two samples.

The 16 samples included a total of 11,497 people who were mostly university students, with seven samples (43.75% of the total samples), adults of the community, with six samples (37.5%), and the remaining three samples of participants recruited from different organizations (18.75%).

The samples of participants came mainly from the USA, with five samples (31.25%), the United Kingdom, with 3 samples (18.75%), Canada, with two samples (12.5%), Australia, with two samples (12.5%), and Sweden, with two samples (12.5%), with the remaining two samples from Portugal and Belgium. To study the influence of the country of origin on the prevalence of psychopathy, the samples were grouped into three categories: North America (USA and Canada: 43.75%), the United Kingdom-Australia (31.25%), and mainland Europe (Sweden, Belgium, and Portugal: 25%).

In nine of the 15 studies listed in Table 1 , psychopathy was evaluated and defined with self-reporting instruments (60% of the studies), whereas in the five other studies, it was done with clinician rating instruments (33.3%). In the remaining study it was done through an interview (6.7%). Among the self-reporting instruments, the most commonly used were the LSRP (Levenson et al., 1995 ) and the SRP of Hare in its different versions (SRP-II, SRP-III, and SRP-SF; Hare, 1990 ; Paulhus et al., 2016 ), each used in three studies, meaning it was used in 66.6% of the self-report studies. With regard to the clinician rating tools, all studies using these instruments used the PCL-R or one of its versions (specifically, the PCL:SV).

Finally, most of the 15 reviewed studies were published in the twenty-first century (12 studies: 80%), especially in the last 10 years (2010–2021: 8 studies, 53.3%), with the three oldest studies published in 1994 and 1995.

Prevalence of Psychopathy in the General Population

Figure 2 presents the prevalence rates of psychopathy found in the 16 samples of the general population analyzed in the present work, and also the joint prevalence rate. The sample prevalence rates ranged from 0 to 21%, with the combined prevalence of 4.5% [95% CI (1.6, 7.9%)].

Forest plot of the prevalence (in proportions) of psychopathy in the general population.

The heterogeneity between the samples was noticeable, as the statistic I 2 = 97.4% [95% CI (96.6, 97.9%)] and a statistically significant Q- test ( Q = 575.22, p < 0.001) were obtained, which justified the analysis of the moderator variables that could partly explain such heterogeneity. Moreover, both the Doi chart and the LFK index suggested that this heterogeneity did not seem to translate into a large asymmetry that could reflect a significant publication bias, because, for example, the LFK index obtained (0.59) was in the range of 1/−1, indicating no asymmetry (see Figure 3 ).

Indicators to evaluate the skewness of the results of the studies and detect the presence of publication biases: Doi chart and LFK index obtained in studies on the prevalence of psychopathy in the general population.

Prevalence of Psychopathy Based on Moderator Variables

The results of the individual meta-regression analyses performed on the prevalence of the 16 samples of the general population indicated that the type of instrument [ F (1, 14) = 5.24, p < 0.038, R 2 = 0.17] and the type of sample [ F (2, 13) = 4.96, p < 0.025, R 2 = 0.52] significantly influenced the prevalence of psychopathy, but not the country of origin of the samples [ F (2, 13) = 0.16, p = 0.857, R 2 = 0.03].

As can be seen in Figure 4 , studies using instruments other than the PCL-R found much higher rates of psychopathy prevalence (more than triple or quadruple, on average) than studies that used the PCL-R or any of its versions, with the combined prevalence of 5.4% [95% CI (1.9, 9.5%)] in the former case, and only of 1.2% [95% CI (0–3.7%)] when using the PCL-R or any of its versions.

Forest plot of the prevalence (in proportions) of psychopathy in the general population depending on the type of instrument used to measure psychopathy: PCL-R vs. other instruments.

For its part, the combined prevalence of psychopathy in samples of organizations [12.9%, 95% CI (3.2, 24.7%)] was higher than in samples of university students [8.1%, 95% CI (5.7, 10.6%)] or in community samples [1.9%, 95% CI (0, 5%)] and, in turn, the joint prevalence among university students was generally higher than among people in the community (8.1 vs. 1.9%) (see Figure 5 ). In fact, in the individual meta-regression analysis, the two binary dummy variables created were statistically significant: organizations vs. non-organizations (β = 0.458, p < 0.022) and college students vs. non-college students (β = 0.297, p < 0.013).

Forest plot of the prevalence (in proportions) of psychopathy in the general population depending on the type of sample evaluated: organizations, community, or university students.

Moreover, when both the type of instruments and the type of samples were included in a multiple meta-regression analysis that, predictably, yielded a statistically significant model [ F (3, 12) = 32.09, p < 0.0001, R 2 = 0.63], only the two binary variables related to the sample type (organizations vs. non-organizations and university students vs. non-university students) continued to be significantly related to the prevalence of psychopathy (β = 0.474, p < 0.003 and β = 0.266, p < 0.032, respectively), whereas the type of instrument did not reach statistical significance (β = 0.198, p < 0.055).

As only 5 of the 15 studies listed in Table 1 offered separate prevalence rates for male and female subsamples (Hagnell et al., 1994 ; Levenson et al., 1995 ; Salekin et al., 2001 ; Neumann and Hare, 2008 ; Coid et al., 2009 ; Love and Holder, 2014 ) and in a sixth study, the sample was entirely male (Robitaille et al., 2017 ), the role of sex as a moderator could only be examined in those six studies, which provided, in total, 13 subsamples/samples.

The results of the individual meta-regression analysis on the prevalence of these 13 subsamples/samples revealed that sex significantly influenced the prevalence of psychopathy, F (1, 11) = 6.00, p < 0.032, R 2 = 0.27. In particular, the combined prevalence of psychopathy was higher (more than double) in males [7.9%, 95% CI (1.6, 15.8%)] than in females [2.9%, 95% CI (0.5, 5.9%)] (see Figure 6 ).

Forest plot of the prevalence (in proportions) of psychopathy in the general population based on gender.

In fact, in the above 13 subsamples/samples, sex was the only moderator significantly related to the prevalence of psychopathy, as neither the country of origin [North Americans vs. Europeans, including the United Kingdom: F (1, 11) = 1.08, p = 0.320, R 2 = 0.08], nor the type of instrument [ F (1, 11) = 4.17, p = 0.065, R 2 = 0.25], nor the type of sample [university students vs. community: F (1, 11) = 4.22, p = 0.064, R 2 = 0.24] proved to be significant in their respective individual meta-regression analyses. However, it should be noted that, in the case of the last two variables, the results showed a trend toward statistical significance that may have been impaired by the fewer subsamples/samples compared with the overall analysis with all the global samples of Table 1 (13 vs. 16 samples).

The main objective of this study was to obtain an estimate of the prevalence of psychopathy in the general adult population and, in this sense, to our knowledge, it is the first systematic or meta-analytic review carried out on this topic. Following a thorough search in the scientific literature, 15 empirical studies were found that had calculated the frequency of psychopathy in samples from the general adult population, including community, organization, and university student samples. These studies used properly described tools and procedures to assess and define psychopathy. After calculating the conjoint mean of their results with meta-analytic procedures, based on a total sample of 11,497 people, it can be estimated that the prevalence of psychopathy in the general adult population is 4.5%.

As could be expected, this prevalence is much lower than that found in samples obtained in forensic or prison contexts. For example, in the meta-analysis of Fox and DeLisi ( 2019 ), it was found that the average prevalence of psychopathy among homicide offenders could be estimated at 27.8 or 34.4%, depending on the criterion used to define psychopathy with the PCL-R (cut-off score of 30 vs. 25, respectively). In the second edition of the PCL-R manual (Hare, 2003a ), the prevalence of psychopathy, based on a cut-off score of 30, was 15.7% for males (Nicholls et al., 2005 ) and 10.3% for females (Guay et al., 2018 ) in the North American normative samples of prisoners.

However, although the average prevalence of psychopathy in the general population is clearly lower than that found in the offender or prison population, the prevalence rates of psychopathy in the general population obtained in the studies reviewed in this work show considerable variation, ranging from a minimum of 0% to a maximum of 21%. In fact, the results obtained in terms of the I 2 and Q statistics confirmed that the heterogeneity of the studies was statistically significant.

These variations depend on many factors, such as the role of the type of instrument used to define psychopathy, the participants' sex, the type of sample of the general population, and the participants' country of origin. These factors have been analyzed in this work. In this sense, the results of the present work indicate that the first three factors, but not the country of origin, seem to have a significant impact on the prevalence of psychopathy. Depending on the chosen instrument, the participants' sex or the type of sample selected, prevalence figures can double, triple, or quadruple the figures found with a different instrument or with participants of another sex or from a different subpopulation of the general population. Moreover, the results obtained in terms of the Doi chart and the LFK index indicate that this heterogeneity does not appear to reflect a significant publication bias, but could largely be attributed to these three moderator variables.

In particular, the results of this work indicate that, when using the PCL-R (or any of its versions), an instrument that is currently considered as the gold standard for the evaluation and definition of psychopathy, it can be estimated that the prevalence of psychopathy in the general adult population is only 1.2%. However, if other instruments are used, such as self-reports of psychopathic personality traits like the LSRP (Levenson et al., 1995 ) or the SRP in their different versions (SRP-II, SRP-III, and SRP-SF; Hare, 1990 ; Paulhus et al., 2016 ), the estimate of the prevalence of psychopathy in the general adult population quadruples, reaching 5.4%.

In fact, as virtually all the studies with offenders use the PCL-R or one of its versions, the comparison between the prevalence rates of psychopathy obtained in the general population and in the offender or prison population should primarily focus on studies conducted with the PCL-R. In this sense, the difference in the prevalence rate of psychopathy between the two types of population, general and criminal, is much greater: 1.2%, obtained in the present work for general population, compared to 15.7 and 10.3%, obtained in the normative samples of the PCL-R for male and female prisoners, respectively (Nicholls et al., 2005 ; Guay et al., 2018 ), or vs. 27.8%, obtained in Fox and DeLisi ( 2019 ) meta-analysis for homicide offenders.

Differences in the prevalence rates as a function of the type of instrument and cut-off point established to identify psychopathy go back to the problems in defining the construct of psychopathy. Those differences also point out a limitation of the present study. We will elaborate on these ideas later in the context of the limitations of this review.

The results of this study also indicate that the prevalence of psychopathy in the general adult population is significantly higher among males than among females. In particular, psychopathy in the general population doubles its prevalence in males compared to females (7.9 vs. 2.9%). This difference is consistent with the results obtained in samples of offenders or incarcerated people, among whom the prevalence of psychopathy is also higher in males than in females (Beryl et al., 2014 ).

In particular, Beryl et al. ( 2014 ) conducted a systematic review of the scientific literature on the prevalence of psychopathy in adult women from within secure settings, which included criminal justice settings, or secure inpatient healthcare settings. They found prevalence rates ranging from 0 to 31% using the PCL-R or one of its versions, although they did not report the average of these rates or the conjoint prevalence. However, from the data they submitted for females in criminal justice settings, it is possible to calculate, for the 13 unique studies that defined psychopathy based on a cut-off score of 30 in the PCL-R or of 18 in the PCL:SV, a weighted average prevalence of 11.9% (Table 3 of Beryl et al., 2014 , p. 191). This figure dropped slightly to 11% when also taking into account the data from the 10 unique studies that had evaluated samples of females in secure/inpatient psychiatric settings or mixed samples—secure/inpatient psychiatric and criminal justice settings—(Tables 2, 4, respectively, of Beryl et al., 2014 , p. 190, 192). Moreover, these figures hardly varied when only studies using the same instrument, the PCL-R, and the same cut-off score, 30 (12.3 and 11.4%, respectively) were taken into account. Interestingly, these prevalence figures are very similar to those presented by the scales of female prisoners collected in the second edition of the PCL-R manual, which, as noted above, show a prevalence of psychopathy in female prisoners of 10.3% (Guay et al., 2018 ). In summary, the average prevalence of psychopathy in female offenders or prisoners can be estimated at 10–12%.

In contrast, in male offenders or prisoners, using the PCL or its versions, rates of average prevalence of psychopathy of 15–35% are usually obtained, although the average rates of 15–25% are probably the most adequate (Hare, 1991 , 2003a ; Guay et al., 2007 ; Fox and DeLisi, 2019 , cited by Nicholls et al., 2005 ). In the 1991 PCL-R manual, Hare reported that, in a global sample of 1,200 males incarcerated in Canadian prisons, 25% scored 30 or higher on the PCL-R. However, in the second edition of the PCL-R manual, published in 2003 and based on a much larger sample with a total of 5,408 males incarcerated in American prisons, Hare reported that 15.7% of the inmates scored 30 or higher on the PCL-R (Hare, 1991 , 2003a ; cited by Nicholls et al., 2005 ). Subsequently, with that same large sample, but eliminating the participants with missing information on some items of the PCL-R ( n = 543), Guay et al. ( 2007 ) reported that 19% of the remaining 4,865 male inmates scored 30 or higher on the PCL-R. Finally, in the meta-analysis of Fox and DeLisi ( 2019 ), it was found that 27.8% of the homicide offenders scored 30 or higher on the PCL-R.

In any case, it seems clear that the prevalence of psychopathy is higher in male offenders or prisoners than in female offenders or prisoners (15–25% vs. 10–12%), and this difference between the sexes is maintained in the general population (7.9 vs. 2.9%), as shown in this meta-analysis.

Another interesting result of this work has to do with the finding of differences in the prevalence of psychopathy between different groups of adults in the general population. In particular, this review has found that the prevalence of psychopathy is significantly higher among workers in some organizations and companies (managers, executives, procurement and supply professionals, advertising workers) than among university students or among people from the general community (12.9 vs. 8.1% and 1.9%, respectively). In turn, the prevalence among university students is significantly higher than among people from the general community (8.1 vs. 1.9%).

The highest prevalence of psychopathy among workers in certain organizations and companies is based on data from only three studies with a total sample of 668 people and should, therefore, be taken with some caution. However, this result is consistent with the scientific literature that proposes that psychopathy is more prevalent in certain professions (e.g., entrepreneurs, managers, politicians, investors, sellers, surgeons, lawyers, telemarketing employees) in which the personality characteristics that define psychopathy could even facilitate their success in these professions (Hare, 2003b ; Dutton, 2012 ; Babiak and Hare, 2019 ; Fritzon et al., 2020 ).

More surprising may be the result that among university students, there is a higher prevalence of psychopathy than among people in the community. Following the previous argument, it could be assumed that among university students of certain professions there could be more people with psychopathic traits (e.g., students in business administration and management, marketing), but it could also be assumed that among university students from other professions, there could be more people with less psychopathic traits and characterized, on the contrary, by high levels of empathy, altruism, candor, trust, humility, and responsibility (e.g., students from health professions, social work, and other professions closely linked to helping). In fact, in a study of Hassall et al. ( 2015 ), it was found that business university students, in comparison to university students of psychology, showed significantly higher levels in the four psychopathy factors measured by the SRP-III (Paulhus et al., 2016 ). Unfortunately, this work did not provide data on the prevalence of psychopathy in the two groups of university students. In addition, in the study of Dutton ( 2012 ), mentioned in the Introduction, among the 10 professions with higher levels of psychopathic traits, there were some that require a university degree (e.g., lawyer, surgeon, journalist) and, likewise, among the 10 professions with lower levels of psychopathic traits, there were also several that require a university degree (e.g., nurse, teacher, doctor).

Therefore, future research with university students should examine whether there are significant differences in psychopathy among students of different careers. This implies that, not only among university students of certain careers may there be a higher prevalence of psychopathy than in the general population, but that among university students of other careers, there may be a similar prevalence. It could even be that among university students of certain careers, there may be a lower prevalence of psychopathy than in the general population.

Research on differences in psychopathy between people of different professions or between university students of different careers departs from the traditional application of the construct of psychopathy to the forensic and prison area. That research intertwines, as discussed in the Introduction, with the most recent interest in the presence of psychopathy in everyday life (Dutton, 2012 ; Babiak and Hare, 2019 ; Fritzon et al., 2020 ), in the definition of psychopathy in terms of normal personality models such as the Big Five model (Lynam and Miller, 2019 ), and in the concept of successful or integrated psychopathy (Dutton, 2012 ; Lilienfeld et al., 2015 ). The fact that, as found in this review, most studies on the prevalence of psychopathy in the general population were published in the twenty-first century, especially in the last 10 years, is also consistent with those most recent interests far from the area of forensic and prison psychology.

Finally, no significant differences in the prevalence of psychopathy in the general population were found in this work as a function of the country of origin of the evaluated people. This absence of differences is not consistent with the results of the scientific literature on criminal and prison populations, which show the existence of differences between countries, especially between North American and European countries, in terms of the prevalence and levels of psychopathy in this type of population. For example, in the review of Beryl et al. ( 2014 ), a trend was found of lower rates of prevalence of psychopathy in European samples of women in prison or in prison hospitals than in American samples. Consistently, in the meta-analysis of Fox and DeLisi ( 2019 ), and after discarding the extreme values from samples composed exclusively of homicides with psychosis or psychopathy, significantly higher levels of PCL-measured psychopathy were found in homicide offenders from the USA and Canada than in homicide offenders from Finland, Sweden, and Germany.

Although these two reviews have reported that psychopathy prevalence is higher in North American male and female offenders and prisoners than in European male and female offenders and prisoners, the reasons for these differences are unclear. Beryl et al. ( 2014 ) suggest that the reason is “that the PCL instruments are designed to test the construct of ‘psychopathy’ as manifested in North American (male) offenders, and are less well-suited to identifying ‘psychopathy’ as manifested in European offenders” (p. 190). However, following the cultural facilitation model and Cooke et al.'s ( 2005 ) suggestions, an alternative reason is that complex social processes, such as socialization and enculturation, can suppress the development of certain aspects of psychopathy and facilitate the development of others. Therefore, it may be that socialization and enculturation in European countries suppress the development of certain psychopathic personality traits, or that those social processes in North American countries facilitate the development of certain psychopathic personality traits. There is also the possibility that both explanations are valid.

In any case, the results of the present review suggest that those differences between countries in the prevalence of psychopathy are unique to the prison or criminal population, but do not extend to the general population.

However, studies using samples from the general population of many different countries around the world have found cultural differences in the levels of different psychopathic traits. For example, in the study of Neumann et al. ( 2012 ) with 33,016 people (19,183 women) from 58 countries belonging to 11 world regions, significant differences were found between these regions in terms of the levels of different psychopathic traits (interpersonal, affective, antisocial, and lifestyle), as measured by one of the brief versions of the Hare SRP (SRP-E).

To further complicate the scenario of empirical results on the relationships between psychopathy and culture, the differences found in some studies with samples from the general population sometimes go in the opposite direction to those found in offender or prisoner populations. Thus, in the study of Lilienfeld et al. ( 2014 ), mentioned in the Introduction, in which they analyzed the responses of 3,338 people to the PPI-R-SF applied online, the Europeans showed higher levels of psychopathic traits than the Americans.

As a result, future research should address whether differences between countries in psychopathy only appear in terms of levels of certain psychopathic traits, but not in terms of the prevalence of psychopathy. When speaking about prevalence of psychopathy, we refer to it as defined by the presence of a clear set of psychopathic traits and with a certain level of intensity of such traits and/or a certain degree of impairment caused by such traits. It should also be examined whether such differences translate into a pattern of consistent differences between North American and European countries.

The results obtained in this work and the conclusions that have been reached should be assessed taking into account some of the limitations of the review itself. The most important limitations concern the high variability of the characteristics of the reviewed studies and the prevalence rates found, the small number of studies conducted to date that can help control such variability, and the methods assessing psychopathy in the reviewed studies. As already mentioned, prevalence rates vary greatly depending on factors such as the type of instrument used to define psychopathy, the participants' sex, and the type of sample from the general population. Given the small number of studies that currently constitute the scientific literature on the prevalence of psychopathy in the general population and the great heterogeneity of these studies in terms of their characteristics, it is very difficult to examine the effects of one of its factors while controlling the effect of the remaining factors. In fact, in this work, the number of subsamples/samples to examine gender prevalence was smaller than for calculating the overall prevalence. Therefore, in that smaller set, factors such as the type of instrument or sample did not reach statistical significance, thus preventing a more statistically potent analysis of the effect of gender after controlling the effects of these two factors and vice versa.

Among the factors that affected the variability of the prevalence of psychopathy, it is worth highlighting the type of instrument used to define psychopathy, since this factor points out important issue underlying this review. There is a high heterogeneity in the methods used to assess psychopathy in the reviewed studies. In addition, some of these method are more susceptible to criticisms related to their reliability and validity than others (e.g., the methods used in Hagnell et al., 1994 ; Gustafson and Ritzer, 1995 ; Pethman and Erlandsson, 2002 ). That heterogeneity and these criticisms go back to the problems in defining the construct of psychopathy. The different theoretical perspectives for this purpose which characterize the research of this construct are also an issue, and have already been discussed in the Introduction. In this sense, for example, an interesting exchange of views has recently been published on the debate over what components are essential to, or constitute part of psychopathy. It has also been discussed whether those components are necessary and/or sufficient (Brislin and Patrick, 2020a , b ; Lynam, 2020 ; Marcus and Nagel, 2020 ). Consequently, one of the most important challenges that research in the area of psychopathy has to face is to achieve a valid and consensual definition of the construct of psychopathy and, related to this, to decide which instrument or instruments are the most valid and reliable to measure this construct. These needs are most evident when studying psychopathy in the general population because, as mentioned above, virtually all studies on psychopathy in the population of offenders or prisoners use the PCL-R or one of its versions (see the reviews of Beryl et al., 2014 , and of Fox and DeLisi, 2019 ).

On the other hand, future research should also focus on the prevalence of the components of psychopathy, especially on the prevalence of psychopathic traits. Moreover, future research should also be conducted on the prevalence of the other personality constructs that are included under the Dark Triad label: Machiavellianism and narcissism.

Despite the above-mentioned limitations, the obtained results reflect relatively strong trends in the data that at least deserve to be the subject of future research and the formation of hypotheses to be taken into account in such research. In short, these trends allow the following conclusions to be drawn:

• The prevalence of psychopathy in the general adult population can be estimated at 4.5%.
• This prevalence is much lower than that found in the offender or prison population, which usually ranges between 10 and 35% (Nicholls et al., 2005 ; Guay et al., 2018 ; Fox and DeLisi, 2019 ).
• The prevalence rates of psychopathy in the general population show considerable variation as a function of the type of instrument used to define psychopathy, the participants' sex, and the type of sample from the general population.
• Using the PCL-R (or any of its versions), lower psychopathy prevalence rates are obtained than if self-reports of psychopathic personality traits are used.
• As the PCL-R is currently considered the “gold standard” for the assessment and definition of psychopathy, the prevalence of psychopathy in the general population may be only 1.2% and, therefore, the difference with the prevalence of the offender or prison population may be even greater.
• As is often the case in the offender and prison population, the prevalence of psychopathy in the general adult population is significantly higher among males than among females.
• The prevalence of psychopathy is significantly higher among workers in some organizations and companies (e.g., managers, executives, procurement and supply professionals, advertising workers) than among university students or people from the general community. In turn, the prevalence of psychopathy among university students is significantly higher than among people from the general community, although the latter result could be due to the type of career that university students are pursuing (e.g., company careers vs. helping careers).

Data Availability Statement

Author's note.

This article is based in part on the final degree project carried out by AS-G under the direction of CG.

Author Contributions

AS-G, CG, and JS contributed to conception and design of the study. AS-G organized the database and wrote the first draft of the manuscript. JS performed the statistical analysis. AS-G, JS, and MG-V wrote sections of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Funding. This work has been made possible in part by a research grant from the Spanish Ministry of Science, Innovation, and Universities (PGC2018-098387-B-I00).

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What Is a Case Study?

Weighing the pros and cons of this method of research

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Cara Lustik is a fact-checker and copywriter.

Verywell / Colleen Tighe

• Pros and Cons

What Types of Case Studies Are Out There?

Where do you find data for a case study, how do i write a psychology case study.

A case study is an in-depth study of one person, group, or event. In a case study, nearly every aspect of the subject's life and history is analyzed to seek patterns and causes of behavior. Case studies can be used in many different fields, including psychology, medicine, education, anthropology, political science, and social work.

The point of a case study is to learn as much as possible about an individual or group so that the information can be generalized to many others. Unfortunately, case studies tend to be highly subjective, and it is sometimes difficult to generalize results to a larger population.

While case studies focus on a single individual or group, they follow a format similar to other types of psychology writing. If you are writing a case study, we got you—here are some rules of APA format to reference.  

At a Glance

A case study, or an in-depth study of a person, group, or event, can be a useful research tool when used wisely. In many cases, case studies are best used in situations where it would be difficult or impossible for you to conduct an experiment. They are helpful for looking at unique situations and allow researchers to gather a lot of˜ information about a specific individual or group of people. However, it's important to be cautious of any bias we draw from them as they are highly subjective.

What Are the Benefits and Limitations of Case Studies?

A case study can have its strengths and weaknesses. Researchers must consider these pros and cons before deciding if this type of study is appropriate for their needs.

One of the greatest advantages of a case study is that it allows researchers to investigate things that are often difficult or impossible to replicate in a lab. Some other benefits of a case study:

• Allows researchers to capture information on the 'how,' 'what,' and 'why,' of something that's implemented
• Gives researchers the chance to collect information on why one strategy might be chosen over another
• Permits researchers to develop hypotheses that can be explored in experimental research

On the other hand, a case study can have some drawbacks:

• It cannot necessarily be generalized to the larger population
• Cannot demonstrate cause and effect
• It may not be scientifically rigorous
• It can lead to bias

Researchers may choose to perform a case study if they want to explore a unique or recently discovered phenomenon. Through their insights, researchers develop additional ideas and study questions that might be explored in future studies.

It's important to remember that the insights from case studies cannot be used to determine cause-and-effect relationships between variables. However, case studies may be used to develop hypotheses that can then be addressed in experimental research.

Case Study Examples

There have been a number of notable case studies in the history of psychology. Much of  Freud's work and theories were developed through individual case studies. Some great examples of case studies in psychology include:

• Anna O : Anna O. was a pseudonym of a woman named Bertha Pappenheim, a patient of a physician named Josef Breuer. While she was never a patient of Freud's, Freud and Breuer discussed her case extensively. The woman was experiencing symptoms of a condition that was then known as hysteria and found that talking about her problems helped relieve her symptoms. Her case played an important part in the development of talk therapy as an approach to mental health treatment.
• Phineas Gage : Phineas Gage was a railroad employee who experienced a terrible accident in which an explosion sent a metal rod through his skull, damaging important portions of his brain. Gage recovered from his accident but was left with serious changes in both personality and behavior.
• Genie : Genie was a young girl subjected to horrific abuse and isolation. The case study of Genie allowed researchers to study whether language learning was possible, even after missing critical periods for language development. Her case also served as an example of how scientific research may interfere with treatment and lead to further abuse of vulnerable individuals.

Such cases demonstrate how case research can be used to study things that researchers could not replicate in experimental settings. In Genie's case, her horrific abuse denied her the opportunity to learn a language at critical points in her development.

This is clearly not something researchers could ethically replicate, but conducting a case study on Genie allowed researchers to study phenomena that are otherwise impossible to reproduce.

There are a few different types of case studies that psychologists and other researchers might use:

• Collective case studies : These involve studying a group of individuals. Researchers might study a group of people in a certain setting or look at an entire community. For example, psychologists might explore how access to resources in a community has affected the collective mental well-being of those who live there.
• Descriptive case studies : These involve starting with a descriptive theory. The subjects are then observed, and the information gathered is compared to the pre-existing theory.
• Explanatory case studies : These   are often used to do causal investigations. In other words, researchers are interested in looking at factors that may have caused certain things to occur.
• Exploratory case studies : These are sometimes used as a prelude to further, more in-depth research. This allows researchers to gather more information before developing their research questions and hypotheses .
• Instrumental case studies : These occur when the individual or group allows researchers to understand more than what is initially obvious to observers.
• Intrinsic case studies : This type of case study is when the researcher has a personal interest in the case. Jean Piaget's observations of his own children are good examples of how an intrinsic case study can contribute to the development of a psychological theory.

The three main case study types often used are intrinsic, instrumental, and collective. Intrinsic case studies are useful for learning about unique cases. Instrumental case studies help look at an individual to learn more about a broader issue. A collective case study can be useful for looking at several cases simultaneously.

The type of case study that psychology researchers use depends on the unique characteristics of the situation and the case itself.

There are a number of different sources and methods that researchers can use to gather information about an individual or group. Six major sources that have been identified by researchers are:

• Archival records : Census records, survey records, and name lists are examples of archival records.
• Direct observation : This strategy involves observing the subject, often in a natural setting . While an individual observer is sometimes used, it is more common to utilize a group of observers.
• Documents : Letters, newspaper articles, administrative records, etc., are the types of documents often used as sources.
• Interviews : Interviews are one of the most important methods for gathering information in case studies. An interview can involve structured survey questions or more open-ended questions.
• Participant observation : When the researcher serves as a participant in events and observes the actions and outcomes, it is called participant observation.
• Physical artifacts : Tools, objects, instruments, and other artifacts are often observed during a direct observation of the subject.

If you have been directed to write a case study for a psychology course, be sure to check with your instructor for any specific guidelines you need to follow. If you are writing your case study for a professional publication, check with the publisher for their specific guidelines for submitting a case study.

Here is a general outline of what should be included in a case study.

Section 1: A Case History

This section will have the following structure and content:

Background information : The first section of your paper will present your client's background. Include factors such as age, gender, work, health status, family mental health history, family and social relationships, drug and alcohol history, life difficulties, goals, and coping skills and weaknesses.

Description of the presenting problem : In the next section of your case study, you will describe the problem or symptoms that the client presented with.

Describe any physical, emotional, or sensory symptoms reported by the client. Thoughts, feelings, and perceptions related to the symptoms should also be noted. Any screening or diagnostic assessments that are used should also be described in detail and all scores reported.

Your diagnosis : Provide your diagnosis and give the appropriate Diagnostic and Statistical Manual code. Explain how you reached your diagnosis, how the client's symptoms fit the diagnostic criteria for the disorder(s), or any possible difficulties in reaching a diagnosis.

Section 2: Treatment Plan

This portion of the paper will address the chosen treatment for the condition. This might also include the theoretical basis for the chosen treatment or any other evidence that might exist to support why this approach was chosen.

• Cognitive behavioral approach : Explain how a cognitive behavioral therapist would approach treatment. Offer background information on cognitive behavioral therapy and describe the treatment sessions, client response, and outcome of this type of treatment. Make note of any difficulties or successes encountered by your client during treatment.
• Humanistic approach : Describe a humanistic approach that could be used to treat your client, such as client-centered therapy . Provide information on the type of treatment you chose, the client's reaction to the treatment, and the end result of this approach. Explain why the treatment was successful or unsuccessful.
• Psychoanalytic approach : Describe how a psychoanalytic therapist would view the client's problem. Provide some background on the psychoanalytic approach and cite relevant references. Explain how psychoanalytic therapy would be used to treat the client, how the client would respond to therapy, and the effectiveness of this treatment approach.
• Pharmacological approach : If treatment primarily involves the use of medications, explain which medications were used and why. Provide background on the effectiveness of these medications and how monotherapy may compare with an approach that combines medications with therapy or other treatments.

This section of a case study should also include information about the treatment goals, process, and outcomes.

When you are writing a case study, you should also include a section where you discuss the case study itself, including the strengths and limitiations of the study. You should note how the findings of your case study might support previous research. 

In your discussion section, you should also describe some of the implications of your case study. What ideas or findings might require further exploration? How might researchers go about exploring some of these questions in additional studies?

Need More Tips?

Here are a few additional pointers to keep in mind when formatting your case study:

• Never refer to the subject of your case study as "the client." Instead, use their name or a pseudonym.
• Read examples of case studies to gain an idea about the style and format.
• Remember to use APA format when citing references .

Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach .  BMC Med Res Methodol . 2011;11:100.

Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach . BMC Med Res Methodol . 2011 Jun 27;11:100. doi:10.1186/1471-2288-11-100

Gagnon, Yves-Chantal.  The Case Study as Research Method: A Practical Handbook . Canada, Chicago Review Press Incorporated DBA Independent Pub Group, 2010.

Yin, Robert K. Case Study Research and Applications: Design and Methods . United States, SAGE Publications, 2017.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

9 things people get wrong about sociopaths, according to a sociopath

• Sociopaths are often depicted as unfeeling criminals and abusers.
• Dr. Patric Gagne, a psychologist and a diagnosed sociopath, wrote a memoir about her experiences.
• She described the many ways she felt misunderstood by others and struggled with finding help.

Diagnosed with sociopathic personality disorder in her 20s, Dr. Patric Gagne struggled to find resources to treat the symptoms she had all her life.

Since childhood, Gagne has felt starkly different from everyone else. She's wrestled with pervasive apathy, and violent urges that feel more calm than charged.

"Everyone else had access to hope," Gagne says in her new memoir, " Sociopath ." "Schizophrenics, alcoholics, bipolar depressives — there were treatment plans and support groups for all of them." Sociopaths in popular culture are "loathsome villains with few exceptions," like Hannibal Lecter in "The Silence of the Lambs" and Patrick Bateman in "American Psycho."

The lack of available care for sociopaths inspired Gagne to pursue a PhD in psychology, where she specialized in the relationship between sociopathy and anxiety. Eventually, she worked as a therapist, where she "earned a low-key reputation as 'the sociopath therapist,'" taking on clients with sociopathic tendencies.

Gagne's memoir cast light on a lot of misconceptions about sociopaths, from how they process emotions to how they form relationships.

1. Sociopaths do feel emotions, just not "social" ones

Sociopaths are often depicted in media as devoid of feelings entirely. But that's not true.

"Some feelings came naturally to me, like anger and happiness," Gagne writes. "But other emotions weren't so easy. Empathy and guilt, embarrassment and jealousy were like a language I couldn't speak or understand." She compares her emotional range to "a cheap set of crayons," where she can access primary colors but struggles with "more nuanced hues."

As an adult researching sociopathy and going to therapy, she learned that sociopaths — and even psychopaths — can feel basic emotions. But they don't experience "social emotions," such as shame, remorse, and even romantic love, because they feel a lack of attachment to people.

2. Anxiety drives violent or risky urges

In pop culture, sociopaths get a thrill out of hurting and manipulating others. But the driver of high-risk and harmful behavior is more complicated, Gagne argues.

She describes feeling a "pressure" and anxiety whenever she feels apathetic. "The nothingness, I'd started to notice, made my urge to do bad things more extreme," Gagne says.

Throughout the book, she tried to mitigate her violent or unlawful urges by committing smaller risky acts, like breaking into people's homes or temporarily stealing cars from drunk fraternity brothers.

Ultimately, she sees her past behavior as a "subconscious drive for feeling." Doing something dangerous didn't actively bring her joy as much as relieve tension and stress — similar, she said, to an OCD compulsion .

3. Unlike psychopaths, they can shows signs of change

"Sociopath" and "psychopath" are often used interchangeably, but there are some key differences . To make matters more confusing, they both fall under the term " antisocial personality disorder ," which Gagne finds unhelpful.

"While I could easily identify with most of the traits on the sociopathic and psychopathic checklists, I was only able to relate to about half of the antisocial ones," she says.

Gagne was diagnosed via a psychopath checklist , where scoring within a lower range indicates sociopathy more than psychopathy because the symptoms are not as extreme.

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While research on the diagnoses is still limited, Gagne says experts believe that, unlike psychopaths, sociopaths can feel anxiety and also show signs of learning right from wrong.

4. They're not devoid of healthy interests or hobbies

Sociopaths are often portrayed as stoic loners in media, with no hobbies other than committing crimes and hurting people.

In truth, they can have interests and hobbies just like anyone else. In the book, Gagne describes her passion for music (particularly jazz), her love for her childhood pet ferret, bonding with the kids she babysits, and becoming fascinated with psychology enough to turn it into a career.

5. They don't understand why some things are "wrong"

Throughout the book, Gagne explains how she finds it difficult to identify "bad" behavior.

"I may have been missing an emotional connection to the concepts of right and wrong, but I knew they existed," she says. Because she can't naturally feel fear, shame, guilt, or remorse, she wouldn't know when she was doing something that could make people uncomfortable or scared, like stealing or stalking.

Later in adulthood, she would try to pay people back when she felt she was doing something wrong. She'd bring flowers to the strangers' funerals she'd crash and fill up the cars she briefly stole with gas.

"One time someone left the stove on, so I turned it off," she said of a house she broke into. "It's my way of trying to balance the karma."

6. They may lie to avoid being judged

A common assumption is that sociopaths always lie for the fun of it, or for personal gain. In Gagne's case, she says she often lied about her feelings just to fit in. She felt claustrophobia whenever she realized she wasn't feeling the way she was "supposed" to, she says in the book.

When her pet ferret died, she felt sadness but couldn't authentically sob the way her sister did. Throughout her childhood, she didn't feel remorse or fear, and sharing that with others didn't help.

That made it hard for her to form genuine connections with others, because she feels like she has to perform or exaggerate emotions to make others comfortable.

7. They crave connection, too

Another big sociopath stereotype is that they're perfectly content being on their own. While Gagne always enjoyed solitude, she also felt loneliness from her inability to be honest about her disorder.

"No one could relate to me," she says. "Nobody wanted to spend time with me. Not the real me, anyway. I was utterly alone."

Over time, she learned how to be more honest, and found people who wouldn't judge her.

8. Treatment can improve their symptoms

In the book, Gagne mentions Dr. Ben Karpman, who theorized that sociopaths "are not hardwired to pursue an antisocial lifestyle and may be responsive to treatment."

Because of the lack of available treatment options, Gagne researched ways to help mitigate her symptoms. She found that cognitive behavioral therapy helped her unpack the feelings of anxiety that triggered unwanted actions. "It all boiled down to mindfulness," she writes.

Acceptance of being a sociopath also helped her, because she realized her anxiety often came from the pressure to fit in. She started to become more open about her diagnosis to reduce the feeling of always needing to hide from others.

9. They can maintain long, healthy relationships

Gagne got married to David, her childhood sweetheart. Together, they share two children, a dog, and a cat.

"I am a passionate mother and wife," she says in the book. "I am an engaging therapist. I am extremely charming and well-liked. I have lots of friends. I am a member of a country club. I throw parties for every occasion you can imagine."

She's been able to have lasting relationships with her friends and family because she sought treatment and answers, which is why she pursued her PhD and started publicly speaking about her experiences.

"I am a twenty-first-century sociopath," she says. "And I've written this book because I know I'm not alone."

Watch: I was assaulted by a Met Police officer at 14, I now train them. Here's how police racism works

• Main content

The Intelligent, Responsible, and Humane Side of Social Media: A Case Study of a Partnership Between UP Police India and Facebook Saving Lives

• Published: 13 April 2024

Cite this article

• Amit Kumar 1 , 2 &
• Vibhuti Gupta   ORCID: orcid.org/0000-0002-8109-0890 3  

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The purpose of the case study is to demonstrate how social media and police (law enforcement) may work together in a thoughtful, ethical, and humanitarian way. By fusing human intelligence with intelligent systems, the case study contends, extraordinary accomplishments can be achieved. Additionally, it underlines the importance of the public-private partnership (PPP) model, in which the joint efforts of two parties; Uttar Pradesh Police (UPP) India and Facebook, representing the public and private sectors, respectively produced incredible results. Phenomenal achievements were made possible by this relationship, and numerous suicide attempts were averted. The case study reviewed cases between March 2022 and February 2024 and found that 321 precious lives were saved due to this partnership. The case study demonstrates how Facebook’s algorithm works to spot any posts that contain language that suggests self-harm or suicide and to issue a warning in the hopes of protecting a precious life. The UP Police’s social media unit gets notified of such posts, thanks to Facebook’s random forest learning algorithms, which then take action to save a priceless life. The case sheds some insight on the privacy concerns of Facebook account holders, the use of sophisticated technology by the police authorities, and its ethical implications as well. It provides some insight into the relevance of management principles to public services.

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Source: Model Adopted from Gupta and Kumar  2021

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Kumar, A., Gupta, V. The Intelligent, Responsible, and Humane Side of Social Media: A Case Study of a Partnership Between UP Police India and Facebook Saving Lives. J Police Crim Psych (2024). https://doi.org/10.1007/s11896-024-09667-w

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