With Medical Marijuana Could Come More Illegal Use

States with medical marijuana laws report higher illicit drug use, Columbia University study says. 

The legalization of marijuana for medical use could come with an unhealthy side effect when it comes to illegal use.

two joints and some marijuana buds

According to researchers at Columbia University Medical Center in New York City, illicit marijuana use, and the disorders that can result, have increased in states that have legalized medical marijuana at a far greater rate than states where marijuana is still illegal.

Medical marijuana is currently legal in 29 states and the District of Columbia. On a national level, marijuana is a Schedule 1 drug, meaning it is viewed as having a high potential for abuse with no medical benefit. While it is a federal offense to distribute marijuana, the federal government under President Obama encouraged federal prosecutors to heed state law when considering marijuana cases.

Medicinal marijuana could have a plethora of health benefits, according to several studies. Cannabis has been shown to control pain, prevent seizures,  and control nausea that results from cancer treatment, among other benefits.

In this study, researchers compared responses from the National Longitudinal Alcohol Epidemiologic Surveys from the years 1991 to 1992, 2001 to 2002 and 2012 to 2013. The surveys used in the study, which are conducted from the National Institutes for Health, covered about 120,000 respondents.

According to the researchers, states that saw medical marijuana become legalized saw “an additional 1.1 million adult illicit cannabis users and an additional 500,000 adults” who exhibited signs of a marijuana use disorder.

“Medical marijuana laws may benefit some with medical problems. However, changing state laws —  medical or recreational — may also have adverse public health consequences, including cannabis use disorders,” lead author Deborah Hasin, PhD, associate professor of Epidemiology and Psychiatry at Columbia University Medical Center, said in a press release. “A prudent interpretation of our results is that professionals and the public should be educated on risks of cannabis use and benefits of treatment, and prevention/intervention services for cannabis disorders should be provided.”

Hasin and team found that marijuana use and abuse did not change much within the first ten-year period. However, from 2002 to 2013, use and abuse increased significantly for states where medical marijuana was legalized. For instance, in states where marijuana is still illegal, use increased from about 4.5 percent to almost 7 percent between 1992 and 2013. In states where medical marijuana was legalized, the jump was from about 6 percent to 9 percent.

According to the study authors, there are a variety of factors that could contribute to these numbers.

“Future studies are needed to investigate mechanisms by which increased cannabis use is associated with medical marijuana laws, including increased perceived safety, availability, and generally permissive attitudes,” Hasin said in the press release.

Hasin and team concluded that in states where marijuana is legal, greater public awareness of the consequences of marijuana abuse and “prevention/intervention services for cannabis disorders should be provided.”

This study was published online on April 26 in the journal JAMA Psychiatry.

The study was funded by the National Institute on Alcohol Abuse and Alcoholism, the Intramural Research Program of the National Institutes of Health, the National Institute on Drug Abuse,  the National Institute on Alcohol Abuse and Alcoholism and the New York State Psychiatric Institute.

No conflicts of interest were reported.

Columbia University Mailman School of Public Health, “Do Medical Marijuana Laws Promote Illicit Cannabis Use and Disorder?”
DEA, “Schedule 1 Drugs”
JAMA Psychiatry, “US Adult Illicit Cannabis Use, Cannabis Use Disorder, and Medical Marijuana Laws”
National Academy of Sciences, “Nearly 100 Conclusions on the Health Effects of Marijuana and Cannabis-Derived Products Presented in New Report…”
NIH, “Available Treatments for Marijuana Use Disorders”
Written by: Neha Kashyap | Medically reviewed by: Dr. Robert Carlson, M.D.