Study: Liberalized Marijuana Laws Have Little Impact on Use Rates Among Adolescents, Young Adults

New York, NY: Policies that either liberalize or eliminate penalties specific to the possession of cannabis appear to have little if any impact on marijuana use rates by those under the age of 25, according to review data published in the journal BMJ Open.

Investigators from Columbia University in New York and INSERM (The Institut national de la santé et de la recherche médicale) in Paris, France reviewed 44 separate studies assessing marijuana use patterns among adolescents (ages 12 to 17) and young adults (ages 18 to 25) following either the decriminalization or legalization of marijuana.

Authors reported that both decriminalization and medical cannabis legalization were "not related to significant changes in patterns of use among adolescents and young people." They suggested that adult-use legalization "appears to possibly result in a small increase" among those age groups (standardized mean difference of 0.03), but also cautioned, "Among studies examining the consequences of the legalization of cannabis for recreational purposes, only one was characterized by a very low risk of bias and five by a low risk of bias; therefore, the findings will need to be confirmed in future research."

They concluded: "Overall, policies regarding cannabis use and possession seem to have little effect on actual patterns of use among young people, with the possible exception of the legalization of recreational use. … It will be important to reassess whether this tendency persists over time, varies across subgroups of youths and is comparable across settings, particularly as additional countries introduce changes in cannabis policy."

Several prior evaluations of marijuana use patterns in states post-legalization show little if any change in cannabis use or access by teenagers, but do show an uptick in use among those in their early-twenties. Most recently, data published online in JAMA Pediatrics reported that states with "recreational marijuana laws were associated with an eight percent decrease in the odds of marijuana use and a nine percent decrease in the odds of frequent marijuana use" among teens.

Full text of the study, "Does liberalization of cannabis policy influence levels of use in adolescents and young adults? A systematic review and meta-analysis," appears in BMJ Open. NORML’s fact-sheet, ‘Marijuana Regulation and Teen Use Rates," appears online.