Passage Of State Medical Marijuana Laws Doesn’t Influence Youth Use

Originally published at blog.NORML.org

The enactment of statewide laws permitting the physician-authorized use of cannabis therapy has not stimulated increases in marijuana use by young people, according to findings published in The International Journal on Drug Policy.

A team of researchers from Columbia University in New York City reviewed federal data regarding rates of self-reported, monthly marijuana use among 12 to 17-year-olds between the years 2002 and 2011.

While the study’s authors acknowledged that many medical marijuana states possess greater overall rates of youth cannabis use compared to non-medical states, they affirmed that these jurisdictions already possessed elevated use rates prior to changes in law, and that the laws’ enactment did not play a role in influencing youth use patterns.

“While states with MML (medical marijuana laws) feature higher rates of adolescent marijuana use, to date, no major U.S. national data set, including the NSDUH (US National Survey on Drug Use in Households), supports that MML are a cause of these higher use levels,” investigators concluded. “[W]hen within-state changes are properly considered and pre-MML prevalence is properly controlled, there is no evidence of a differential increase in past-month marijuana use in youth that can be attributed to state medical marijuana laws.”

Their findings are similar to those of a separate 2015 study assessing 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 in that study reported no increase in teens’ overall cannabis use that could be attributable to changes in law, and acknowledged a “robust” decrease in consumption among 8th graders. They concluded “[T]he results of this study showed no evidence for an increase in adolescent marijuana use after the passage of state laws permitting use of marijuana for medical purposes. … [C]oncerns that increased marijuana use is an unintended effect of state marijuana laws seem unfounded.”

Other studies reaching similar conclusions are available here, here, here, here, and here.

The abstract of the study, “Prevalence of marijuana use does not differentially increase among youth after states pass medical marijuana laws: Commentary on and reanalysis of US National Survey on Drug Use in Households data 2002-2011,” appears online here.