thesis on legalizing marijuana

• Program Finder
• Admissions Services
• Course Directory
• Academic Calendar
• Hybrid Campus
• Lecture Series
• Convocation
• Strategy and Development
• Implementation and Impact
• Integrity and Oversight
• In the School
• In the Field
• In Baltimore
• Resources for Practitioners
• Articles & News Releases
• In The News
• Statements & Announcements
• At a Glance
• Student Life
• Strategic Priorities
• Inclusion, Diversity, Anti-Racism, and Equity (IDARE)
• What is Public Health?

The Evidence—and Lack Thereof—About Cannabis

Research is still needed on cannabis’s risks and benefits. 

Lindsay Smith Rogers

Although the use and possession of cannabis is illegal under federal law, medicinal and recreational cannabis use has become increasingly widespread.

Thirty-eight states and Washington, D.C., have legalized medical cannabis, while 23 states and D.C. have legalized recreational use. Cannabis legalization has benefits, such as removing the product from the illegal market so it can be taxed and regulated, but science is still trying to catch up as social norms evolve and different products become available. 

In this Q&A, adapted from the August 25 episode of Public Health On Call , Lindsay Smith Rogers talks with Johannes Thrul, PhD, MS , associate professor of Mental Health , about cannabis as medicine, potential risks involved with its use, and what research is showing about its safety and efficacy. 

Do you think medicinal cannabis paved the way for legalization of recreational use?

The momentum has been clear for a few years now. California was the first to legalize it for medical reasons [in 1996]. Washington and Colorado were the first states to legalize recreational use back in 2012. You see one state after another changing their laws, and over time, you see a change in social norms. It's clear from the national surveys that people are becoming more and more in favor of cannabis legalization. That started with medical use, and has now continued into recreational use.

But there is a murky differentiation between medical and recreational cannabis. I think a lot of people are using cannabis to self-medicate. It's not like a medication you get prescribed for a very narrow symptom or a specific disease. Anyone with a medical cannabis prescription, or who meets the age limit for recreational cannabis, can purchase it. Then what they use it for is really all over the place—maybe because it makes them feel good, or because it helps them deal with certain symptoms, diseases, and disorders.

Does cannabis have viable medicinal uses?

The evidence is mixed at this point. There hasn’t been a lot of funding going into testing cannabis in a rigorous way. There is more evidence for certain indications than for others, like CBD for seizures—one of the first indications that cannabis was approved for. And THC has been used effectively for things like nausea and appetite for people with cancer.

There are other indications where the evidence is a lot more mixed. For example, pain—one of the main reasons that people report for using cannabis. When we talk to patients, they say cannabis improved their quality of life. In the big studies that have been done so far, there are some indications from animal models that cannabis might help [with pain]. When we look at human studies, it's very much a mixed bag. 

And, when we say cannabis, in a way it's a misnomer because cannabis is so many things. We have different cannabinoids and different concentrations of different cannabinoids. The main cannabinoids that are being studied are THC and CBD, but there are dozens of other minor cannabinoids and terpenes in cannabis products, all of varying concentrations. And then you also have a lot of different routes of administration available. You can smoke, vape, take edibles, use tinctures and topicals. When you think about the explosion of all of the different combinations of different products and different routes of administration, it tells you how complicated it gets to study this in a rigorous way. You almost need a randomized trial for every single one of those and then for every single indication.

What do we know about the risks of marijuana use?  

Cannabis use disorder is a legitimate disorder in the DSM. There are, unfortunately, a lot of people who develop a problematic use of cannabis. We know there are risks for mental health consequences. The evidence is probably the strongest that if you have a family history of psychosis or schizophrenia, using cannabis early in adolescence is not the best idea. We know cannabis can trigger psychotic symptoms and potentially longer lasting problems with psychosis and schizophrenia. 

It is hard to study, because you also don't know if people are medicating early negative symptoms of schizophrenia. They wouldn't necessarily have a diagnosis yet, but maybe cannabis helps them to deal with negative symptoms, and then they develop psychosis. There is also some evidence that there could be something going on with the impact of cannabis on the developing brain that could prime you to be at greater risk of using other substances later down the road, or finding the use of other substances more reinforcing. 

What benefits do you see to legalization?

When we look at the public health landscape and the effect of legislation, in this case legalization, one of the big benefits is taking cannabis out of the underground illegal market. Taking cannabis out of that particular space is a great idea. You're taking it out of the illegal market and giving it to legitimate businesses where there is going to be oversight and testing of products, so you know what you're getting. And these products undergo quality control and are labeled. Those labels so far are a bit variable, but at least we're getting there. If you're picking up cannabis at the street corner, you have no idea what's in it. 

And we know that drug laws in general have been used to criminalize communities of color and minorities. Legalizing cannabis [can help] reduce the overpolicing of these populations.

What big questions about cannabis would you most like to see answered?

We know there are certain, most-often-mentioned conditions that people are already using medical cannabis for: pain, insomnia, anxiety, and PTSD. We really need to improve the evidence base for those. I think clinical trials for different cannabis products for those conditions are warranted.

Another question is, now that the states are getting more tax revenue from cannabis sales, what are they doing with that money? If you look at tobacco legislation, for example, certain states have required that those funds get used for research on those particular issues. To me, that would be a very good use of the tax revenue that is now coming in. We know, for example, that there’s a lot more tax revenue now that Maryland has legalized recreational use. Maryland could really step up here and help provide some of that evidence.

Are there studies looking into the risks you mentioned?

Large national studies are done every year or every other year to collect data, so we already have a pretty good sense of the prevalence of cannabis use disorder. Obviously, we'll keep tracking that to see if those numbers increase, for example, in states that are legalizing. But, you wouldn't necessarily expect to see an uptick in cannabis use disorder a month after legalization. The evidence from states that have legalized it has not demonstrated that we might all of a sudden see an increase in psychosis or in cannabis use disorder. This happens slowly over time with a change in social norms and availability, and potentially also with a change in marketing. And, with increasing use of an addictive substance, you will see over time a potential increase in problematic use and then also an increase in use disorder.

If you're interested in seeing if cannabis is right for you, is this something you can talk to your doctor about?

I think your mileage may vary there with how much your doctor is comfortable and knows about it. It's still relatively fringe. That will very much depend on who you talk to. But I think as providers and professionals, everybody needs to learn more about this, because patients are going to ask no matter what.

Lindsay Smith Rogers, MA, is the producer of the Public Health On Call podcast , an editor for Expert Insights , and the director of content strategy for the Johns Hopkins Bloomberg School of Public Health.

Could Medical Marijuana Help Address the Opioid Epidemic?

Policy Is Public Health

Medical Marijuana Laws Linked to Health and Labor Supply Benefits in Older Adults

Related Content

Research Identifies Characteristics of Cities That Would Support Young People’s Mental Health

Alumni Spotlight: Junrui Di, PhD '19

Child Diarrhea Has a Cheap and Easy Fix—Why Isn’t It Reaching Patients?

How Abortion Trigger Laws Impact Mental Health

Bridging the Surgical Gap for Rural Indigenous Communities

2018 Theses Doctoral

Essays on Cannabis Legalization

Thomas, Danna Kang

Though the drug remains illegal at the federal level, in recent years states and localities have increasingly liberalized their marijuana laws in order to generate tax revenue and save resources on marijuana law enforcement. Many states have adopted some form of medical marijuana and/or marijuana decriminalization laws, and as of 2017, Washington, Colorado, Maine, California, Oregon, Massachusetts, Nevada, Alaska, and the District of Columbia have all legalized marijuana for recreational use. In 2016 recreational marijuana generated over $1.8 billion in sales. Hence, studying marijuana reforms and the policies and outcomes of early recreational marijuana adopters is an important area of research. However, perhaps due to the fact that legalized recreational cannabis is a recent phenomenon, a scarcity of research exists on the impacts of recreational cannabis legalization and the efficacy and efficiency of cannabis regulation. This dissertation aims to fill this gap, using the Washington recreational marijuana market as the primary setting to study cannabis legalization in the United States. Of first order importance in the regulation of sin goods such as cannabis is quantifying the value of the marginal damages of negative externalities. Hence, Chapter 1 (co-authored with Lin Tian) explores the impact of marijuana dispensary location on neighborhood property values, exploiting plausibly exogenous variation in marijuana retailer location. Policymakers and advocates have long expressed concerns that the positive effects of the legalization--e.g., increases in tax revenue--are well spread spatially, but the negative effects are highly localized through channels such as crime. Hence, we use changes in property values to measure individuals' willingness to pay to avoid localized externalities caused by the arrival of marijuana dispensaries. Our key identification strategy is to compare changes in housing sales around winners and losers in a lottery for recreational marijuana retail licenses. (Due to location restrictions, license applicants were required to provide an address of where they would like to locate.) Hence, we have the locations of both actual entrants and potential entrants, which provides a natural difference-in-differences set-up. Using data from King County, Washington, we find an almost 2.4% decrease in the value of properties within a 0.5 mile radius of an entrant, a $9,400 decline in median property values. The aforementioned retail license lottery was used to distribute licenses due to a license quota. Retail license quotas are often used by states to regulate entry into sin goods markets as quotas can restrict consumption by decreasing access and by reducing competition (and, therefore, increasing markups). However, license quotas also create allocative inefficiency. For example, license quotas are often based on the population of a city or county. Hence, licenses are not necessarily allocated to the areas where they offer the highest marginal benefit. Moreover, as seen in the case of the Washington recreational marijuana market, licenses are often distributed via lottery, meaning that in the absence of an efficiency secondary market for licenses, the license recipients are not necessarily the most efficient potential entrants. This allocative inefficiency is generated by heterogeneity in firms and consumers. Therefore, in Chapter 2, I develop a model of demand and firm pricing in order to investigate firm-level heterogeneity and inefficiency. Demand is differentiated by geography and incorporates consumer demographics. I estimate this demand model using data on firm sales from Washington. Utilizing the estimates and firm pricing model, I back out a non-parametric distribution of firm variable costs. These variable costs differ by product and firm and provide a measure of firm inefficiency. I find that variable costs have lower inventory turnover; hence, randomly choosing entrants in a lottery could be a large contributor to allocative inefficiency. Chapter 3 explores the sources of allocative inefficiency in license distribution in the Washington recreational marijuana market. A difficulty in studying the welfare effects of license quotas is finding credible counterfactuals of unrestricted entry. Therefore, I take a structural approach: I first develop a three stage model that endogenizes firm entry and incorporates the spatial demand and pricing model discussed in Chapter 2. Using the estimates of the demand and pricing model, I estimate firms' fixed costs and use data on locations of those potential entrants that did not win Washington's retail license lottery to simulate counterfactual entry patterns. I find that allowing firms to enter freely at Washington's current marijuana tax rate increases total surplus by 21.5% relative to a baseline simulation of Washington's license quota regime. Geographic misallocation and random allocation of licenses account for 6.6\% and 65.9\% of this difference, respectively. Moreover, as the primary objective of these quotas is to mitigate the negative externalities of marijuana consumption, I study alternative state tax policies that directly control for the marginal damages of marijuana consumption. Free entry with tax rates that keep the quantity of marijuana or THC consumed equal to baseline consumption increases welfare by 6.9% and 11.7%, respectively. I also explore the possibility of heterogeneous marginal damages of consumption across geography, backing out the non-uniform sales tax across geography that is consistent with Washington's license quota policy. Free entry with a non-uniform sales tax increases efficiency by over 7% relative to the baseline simulation of license quotas due to improvements in license allocation.

• Cannabis--Law and legislation
• Marijuana industry
• Drug legalization
• Drugs--Economic aspects

More About This Work

• DOI Copy DOI to clipboard

THREE ESSAYS ON THE EFFECT OF LEGALIZING MARIJUANA ON HEALTH, EDUCATION, AND SOCIAL SECURITY

The legalization of marijuana has emerged as a critical public policy issue, with far-reaching implications for health, education, and government programs at both the state and federal levels. The three essays of this dissertation show that medical marijuana legalization (MML) has a negative effect in each of these areas. The first essay shows, that the enactment of MMLs can exacerbate the crisis of overdose deaths in the United States. The study analyzes three key areas: the rate of overdose deaths caused by both legal and illegal drugs, the impact of MML on social norms regarding the perceived harm of marijuana, and an investigation into the gateway theory by examining the use of other addictive drugs. I find that MMLs increase deaths attributed to overdose by 21.5% population. MMLs s also indicate increase the number of deaths due to prescribed opioids by 44.6%, and deaths from all opioids (heroin and cocaine in addition to prescribed opioids) by 37.2 % Results suggest an overall increase in the use of marijuana, primarily due to lower perceived risk among adolescents. Additionally, results show an increase in hospital admissions due to substance abuse. The analysis suggests that legalizing medical marijuana may exaggerate the current problem of drug overdose in the United States. The second essay examines the impact of improved access to medical marijuana, measured by the proximity of schools to the nearest dispensary, on the academic performance of high school students in California. Students in schools farther from a marijuana dispensary have higher academic performance as measured through AP, ACT, SAT scores, and average GPA, and lower number of suspensions due to violence and illicit drug use. To show this, I construct the first geocoded dataset on marijuana dispensary and high school locations, use newly developed difference-in-differences estimators that rule out any bias due to heterogeneous treatment effects over time, and explore dynamic responses. This essay reveals the importance of ensuring a largest possible distance between schools and dispensaries to protect adolescents from the potential harm caused by medical marijuana. Finally, the third essay shows that in the long term, MMLs increase the number of disabled workers who receive Social Security Disability Income (SSDI) because of mental health issues. SSDI is a major social insurance program that provides benefits to workers who become disabled, and understanding how policy changes in other areas may impact this program is important. In this study, there were important differences between the results of a two-way fixed effects model and a new model by Callaway and Santa’Anna. MMLs, in theory, could either increase or decrease the number of SSDI recipients, and traditional fixed effects models suggest both could be at play; however, only the negative effect is robust to correction for heterogeneous effects. This highlights the need for future research to understand the true impact of medical marijuana legalization

Contributors

Degree grantor, degree level, submission id, usage metrics.

• Health economics
• Welfare economics
• Epidemiology
• Health policy
• Public policy
• Medical and health law

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.110(6); Nov-Dec 2013

More Reasons States Should Not Legalize Marijuana: Medical and Recreational Marijuana: Commentary and Review of the Literature

Recent years have seen substantial shifts in cultural attitudes towards marijuana for medical and recreational use. Potential problems with the approval, production, dispensation, route of administration, and negative health effects of medical and recreational marijuana are reviewed. Medical marijuana should be subject to the same rigorous approval process as other medications prescribed by physicians. Legalizing recreational marijuana may have negative public health effects.

Introduction

Recent years have seen a cultural shift in attitudes towards marijuana. At the time of this writing, medical marijuana is legal in 20 states and the District of Columbia; recreational marijuana is now legal in Washington and Colorado. A substantial and growing literature documents legalized marijuana may have adverse effects on individual and public health.

Medical Use of Marijuana

The term ‘medical marijuana’ implies that marijuana is like any other medication prescribed by a physician. Yet the ways in which medical marijuana has been approved, prescribed, and made available to the public are very different from other commercially available prescription drugs. These differences pose problems unrecognized by the public and by many physicians.

Lack of Evidence for Therapeutic Benefit

In the United States, commercially available drugs are subject to rigorous clinical trials to evaluate safety and efficacy. Data appraising the effectiveness of marijuana in conditions such as HIV/AIDS, epilepsy, and chemotherapy-associated vomiting is limited and often only anecdotal. 1 , 2 To date, there has been only one randomized, double-blind, placebo- and active-controlled trial evaluating the efficacy of smoked marijuana for any of its potential indications, which showed that marijuana was superior to placebo but inferior to Ondansetron in treating nausea. 3 Recent reviews by the Cochrane Collaboration find insufficient evidence to support the use of smoked marijuana for a number of potential indications, including pain related to rheumatoid arthritis, 4 dementia, 5 ataxia or tremor in multiple sclerosis, 6 and cachexia and other symptoms in HIV/AIDS. 2 This does not mean, of course, that components of marijuana do not have potential therapeutic effects to alleviate onerous symptoms of these diseases; but, given the unfavorable side effect profile of marijuana, the evidence to justify use in these conditions is still lacking.

Contamination, Concentration & Route of Administration

Unlike any other prescription drug used for medical purposes, marijuana is not subject to central regulatory oversight. It is grown in dispensaries, which, depending on the state, have regulatory standards ranging from strict to almost non-existent. The crude marijuana plant and its products may be contaminated with fungus or mold. 7 This is especially problematic for immunocompromised patients, 8 including those with HIV/AIDS or cancer. 9 Furthermore, crude marijuana contains over 60 active cannabinoids, 10 few of which are well studied. Marijuana growers often breed their plants to alter the concentrations of different chemicals compounds. For instance, the concentration of tetrahydrocannabinol (THC), the principal psychoactive ingredient, is more than 20-fold more than in marijuana products used several decades ago. Without rigorous clinical trials, we have no way of knowing which combinations of cannabinoids may be therapeutic and which may be deleterious. As marijuana dispensaries experiment by breeding out different cannabinoids in order to increase the potency of THC, there may be unanticipated negative and lasting effects for individuals who smoke these strains.

Marijuana is the only ‘medication’ that is smoked, and, while still incompletely understood, there are legitimate concerns about long-term effects of marijuana smoke on the lungs. 11 , 12 Compared with cigarette smoke, marijuana smoke can result in three times the amount of inhaled tar and four times the amount of inhaled carbon-monoxide. 13 Further, smoking marijuana has been shown to be a risk factor for lung cancer in many 14 , 15 but not all 16 studies.

High Potential for Diversion

In some states, patients are permitted to grow their own marijuana. In addition to contributing to problems such as contamination and concentration as discussed above, this practice also invites drug diversion. Patients seeking to benefit financially may bypass local regulations of production and sell home-grown marijuana at prices lower than dispensaries. We do not allow patient to grow their own opium for treatment of chronic pain; the derivatives of opium, like marijuana, are highly addictive and thus stringently regulated.

Widespread “Off-label” Use

FDA-approved forms of THC (Dronabinol) and a THC-analog (Nabilone), both available orally, already exist. Indications for these drugs are HIV/AIDS cachexia and chemotherapy-associated nausea and vomiting. Unlike smoked, crude marijuana, these medications have been subject to randomized, placebo-controlled, clinical trials. Yet despite these limited indications where marijuana compounds have a proven but modest effect in high-quality clinical trials, medical marijuana is used overwhelmingly for non-specific pain or muscle spasms. Recent data from Colorado show that 94% of patients with medical marijuana cards received them for treatment of “severe pain.” 17 Similar trends are evident in California. 18 Evidence for the benefit of marijuana in neuropathic pain is seen in many 19 - 21 but not all 22 clinical trials. There is no high-quality evidence, however, that the drug reduces non-neuropathic pain; this remains an indication for which data sufficient to justify the risks of medical marijuana is lacking. 4 , 23 – 25

If marijuana is to be ‘prescribed’ by physicians and used as a medication, it should be subject to the same rigorous approval process that other commercially available drugs undergo. Potentially therapeutic components of marijuana should be investigated, but they should only be made available to the public after adequately powered, double-blind, placebo-controlled trials have demonstrated efficacy and acceptable safety profiles. Furthermore, these compounds should be administered in a way that poses less risk than smoking and dispensed via standardized and FDA-regulated pharmacies to ensure purity and concentration. Bypassing the FDA and approving ‘medicine’ at the ballot box sets a dangerous precedent. Physicians should be discouraged from recommending medical marijuana. Alternatively, consideration can be given to prescribing FDA-approved medicines (Dronabinol or Cesamet) as the purity and concentration of these drugs are assured and their efficacy and side effect profiles have been well documented in rigorous clinical trials.

Recreational Marijuana

The question of recreational marijuana is a broader social policy consideration involving implications of the effects of legalization on international drug cartels, domestic criminal justice policy, and federal and state tax revenue in addition to public health. Yet physicians, with a responsibility for public health, are experts with a vested interest in this issue. Recent legislation, reflecting changes in the public’s attitudes towards marijuana, has permitted the recreational use of marijuana in Colorado and Washington. Unfortunately, the negative health consequences of the drug are not prominent in the debate over legalizing marijuana for recreational use. In many cases, these negative effects are more pronounced in adolescents. A compelling argument, based on these negative health effects in both adolescents and adults, can be made to abort the direction society is moving with regards to the legalization of recreational marijuana.

Myth: Marijuana is Not Addictive

A growing myth among the public is that marijuana is not an addictive substance. Data clearly show that about 10% of those who use cannabis become addicted; this number is higher among adolescents. 26 Users who seek treatment for marijuana addiction average 10 years of daily use. 27 A withdrawal syndrome has been described, consisting of anxiety, restlessness, insomnia, depression, and changes in appetite 28 and affects as many as 44% of frequent users, 29 contributing to the addictive potential of the drug. This addictive potential may be less than that of opiates; but the belief, especially among adolescents, that the drug is not addictive is misguided.

Schizophrenia and Other Psychotic Disorders

Marijuana has been consistently shown to be a risk factor for schizophrenia and other psychotic disorders. 30 – 32 The association between marijuana and schizophrenia fulfills many, but not all, of the standard criteria for the epidemiological establishment of causation, including experimental evidence, 33 , 34 temporal relationship, 35 – 38 biological gradient, 30 , 31 , 39 and biological plausibility. 40 Genetic variation may explain why marijuana use does not strongly fulfill remaining criteria, such as strength of association and specificity. 41 , 42 As these genetic variants are explored and further characterized, marijuana use may be shown to cause or precipitate schizophrenia in a genetically vulnerable population. The risk of psychotic disorder is more pronounced when marijuana is used at an earlier age. 32 , 43

There is some evidence that compounds naturally found in marijuana have therapeutic benefit for symptoms of diseases such as HIV/AIDS, multiple sclerosis, and cancer. If these compounds are to be used under the auspices of ‘medical marijuana,’ they should undergo the same rigorous approval process that other medications prescribed by physicians, including randomized, placebo- and active-controlled trials to evaluate safety and efficacy, not by popular vote or state legislature.

Effects on Cognition

Early studies suggested cognitive declines associated with marijuana (especially early and heavy use); these declines persisted long after the period of acute cannabis intoxication. 44 – 46 Recently, Meier and colleagues analyzed data from a prospective study which followed subjects from birth to age 38; their findings yielded supportive evidence that cannabis use, when begun during adolescence, was associated with cognitive impairment in multiple areas, including executive functioning, processing speed, memory, perceptual reasoning, and verbal comprehension. 47 Rogeberg 48 criticized the study’s methodology, claiming that the results were confounded by differences in socioeconomic status; this claim, however, was based on sub-analyses that used very small numbers. Additional sub-analyses 49 of the original study cohort showed that marijuana was just as prevalent in populations of higher socioeconomic status, suggesting that socioeconomic status was not a confounding variable. Any epidemiological study is subject to confounding biases and future research will be needed to clarify and quantify the relationship between cognitive decline and adolescent marijuana use. However, the findings of the original study by Meier et al show there is indeed an independent relationship between loss of intelligence and adolescent marijuana use. This finding, moreover, is consistent with prior studies. 44

Other Negative Health Effects

Substantial evidence exists suggesting that marijuana is harmful to the respiratory system. It is associated with symptoms of obstructive and inflammatory lung disease, 11 , 50 an increased risk of lung cancer, 14 , 15 and it is suspected to be associated with reduced pulmonary function in heavy users. 51 Further, its use has been associated with harmful effects to other organ systems, including the reproductive, 52 gastrointestinal, 53 and immunologic 10 , 54 systems.

Social Safety Implications: Effects on Driving

Marijuana impairs the ability to judge time, distance, and speed; it slows reaction time and reduces ability to track moving objects. 55 , 56 In many studies of drug-related motor vehicle fatalities, marijuana is the most common drug detected except for alcohol. 57 , 58 Based on post-mortem studies, Couch et al determined that marijuana was likely an impairing factor in as many fatal accidents as alcohol. 59 One study showed that in motor vehicle accidents where the driver was killed, recent marijuana use was detected in 12% of cases. 57 Other research confirms a significantly increased risk of motor vehicle fatalities in association with acute cannabis intoxication. 60

Risk Perception and Use in Adolescents

Marijuana use among adolescents has been increasing. Data that has tracked risk perception and use of marijuana among adolescents over decades clearly shows an inverse relationship; as adolescent risk perception wanes, marijuana use increases. 61 As more states legalize medical and recreational marijuana, risk perception is expected to decrease, causing the prevalence of use among adolescent to continue to rise. This is among the most concerning of issues about the drug’s legalization because so many of the negative effects of marijuana—including cognitive impairment and risk for short- and long-term psychosis— are heightened when used during adolescence.

There is some evidence that compounds naturally found in marijuana have therapeutic benefit for symptoms of diseases such as HIV/AIDS, multiple sclerosis, and cancer. If these compounds are to be used under the auspices of ‘medical marijuana,’ they should undergo the same rigorous approval process that other medications prescribed by physicians, including randomized, placebo- and active-controlled trials to evaluate safety and efficacy, not by popular vote or state legislature. Furthermore, these therapeutic compounds should be administered via a route that minimizes long-term health risk (i.e., via oral pill) and should be dispensed by centrally regulated pharmacies to ensure the purity and concentration of the drug and allow for the recall of contaminated batches.

Marijuana for recreational use will have many adverse health effects. The drug is addictive, with mounting evidence for the existence of a withdrawal syndrome. Furthermore, it has been shown to have adverse effects on mental health, intelligence (including irreversible declines in cognition), and the respiratory system. Driving while acutely intoxicated with marijuana greatly increases the risk of fatal motor vehicle collision. Legalization for recreational use may have theoretical (but still unproven) beneficial social effects regarding issues such as domestic criminal justice policy, but these effects will not come without substantial public health and social costs. Currently there is a lack of resources devoted to educating physicians about this most commonly used illicit substance. The potential benefits and significant risks associated with marijuana use should be taught in medical schools and residency programs throughout the country.

Samuel T. Wilkinson, MD, is in the Department of Psychiatry at the Yale School of Medicine, New Haven, Ct.

Contact: [email protected]

None reported.