Federal Study: Passage of Medical Marijuana Laws Don’t Increase Teen Use

The enactment of state laws legalizing the use and distribution of cannabis for medical purposes has not caused an increase in marijuana use by adolescents, according to the results of a federally funded study published this week in Lancet Psychiatry.

Investigators at Columbia University in New York and the University of Michigan assessed the relationship between state medical marijuana laws and rates of self-reported adolescent marijuana use over a 24-year period in a sampling of over one million adolescents in 48 states. Researchers reported no increase in teens’ overall use of the plant that could be attributable to changes in law, and acknowledged a “robust” decrease in use among 8th graders.

They concluded: “[T]he results of this study showed no evidence for an increase in…