Despite what many fear, a new study finds medical marijuana laws do not cause more teens to use the drug.
Researchers at Brown University compared teen marijuana use in 10 U.S. states that were similar but differed in one significant way — the presence or absence of medical marijuana laws. The results showed no correlation between marijuana legalization and a rise in use among high school students.
“Our study suggests that — at least thus far — the legalization of marijuana for medical purposes has not increased adolescent marijuana use, a finding supported by a growing body of literature,” writes study author Dr. Esther K. Choo.
The results were published earlier this year in the Journal of Adolescent Health.
Teen use of recreational cannabis was measured based on the results of the Youth Risk Behaviour Surveillance System (YRBS). The bi-annual survey of 9th to 12th grade students is overseen by the Centers for Disease Control and Prevention (CDC) and measures the prevalence of health-risk behaviors, including alcohol and other drug use.
“States with a medical marijuana law for which at least two cycles of YRBS data were available before and after the implementation of the law were selected for analysis,” explains Choo.
“Each of these states was paired with a state in geographic proximity that had not implemented the law.”
Choo builds on the work of previous researchers. In 2012, a team from McGill University reviewed teen marijuana use in states with medical marijuana laws and concluded that any relationship was “unlikely to be a causal association.”
The following year, University of Florida researchers compared data across four states, observing that medical marijuana laws “do not appear to have significantly increased the prevalence or frequency of adolescent marijuana use in the first few years after their enactment.”
The latest study revealed another interesting pattern; in some cases, legalization of medical marijuana led to a slight decrease in teen use in that state.
“It may be that normalizing marijuana use through medical legalization, as well as associating its use with chronically or even terminally ill populations, makes the use of the drug less appealing to adolescents,” Choo suggests.
Another explanation for the decrease may be that adolescents are registering for medical marijuana exemptions under newly introduced state regulations, and as a result no longer report cannabis use under the health-risk behaviors measured by the YRBS.
As well, the acceptance of some marijuana use by state authorities may allow teenagers to feel more comfortable asking for assistance with harmful use of the drug.
Whatever the reason, Choo’s finding are supported by empirical evidence presented by a 2007 study, which found that criminalizing marijuana deterred adults but not youth under the age of 21.
The findings also contradict the concerns expressed by marijuana prohibition supporters who claim that legalizing cannabis will increase its use among high school students. However, to be sure, the report recommends future long-term studies.