Marijuana Policy Project

Replicating a prior study, but controlling for state characteristics and measurement error, researchers found that medical marijuana laws have little discernible impact on teen marijuana use or perceptions of the risk of marijuana use in those states. In fact, their research showed that passage of medical marijuana laws actually resulted in a slight decrease in teen marijuana use.

This article examines the subjective impact of medical cannabis on the use of both licit and illicit substances via self-report from 404 medical cannabis patients recruited from four dispensaries in British Columbia, Canada. A 44-question survey was used to anonymously gather data on the self-reported impact of medical cannabis on the use of other substances. Over 41% state that they use cannabis as a substitute for alcohol, 36.1% use cannabis as a substitute for illicit substances, and 67.8% use cannabis as a substitute for prescription drugs. The three main reasons cited for cannabis-related substitution are “less withdrawal,” “fewer side-effects,” and “better symptom management.”

Using data from the national and state Youth Risk Behavior Surveys and other government sponsored data collections, researchers from the Universities of Washington, Oregon, and Colorado at Denver found no association between medical marijuana laws and increased teen marijuana use. They concluded, "[o]ur results are not consistent with the hypothesis that legalization leads to increased use of marijuana by teenagers."