Youth marijuana use does not increase after states enact legalization for medical or adult use, researchers concluded in a study published in a prominent scientific journal on Tuesday. The policy change instead has an overall impact on adolescent cannabis consumption that is “statistically indistinguishable from zero,” they found.
In fact, it seems that establishing certain regulated cannabis models actually leads to lower marijuana use among adolescents under certain measures—a finding that directly conflicts with anti-legalization arguments that are commonly made by prohibitionists.
The analysis, published by the Journal of the American Medical Association, analyzed federal Youth Risk Behavior Survey data from 1993-2019 in 10 medical or adult-use states. It builds upon existing studies on the impact of cannabis reform on youth consumption that have reached similar conclusions.
Researchers determined that the adoption of recreational cannabis legalization “was not associated with current marijuana use or frequent marijuana use.”
Further, “medical marijuana law (MML) adoption was associated with a 6-percent decrease in the odds of current marijuana use and a 7-percent decrease in the odds of frequent marijuana use.”
The study, which received partial funding through a federal National Institutes of Health grant, also found that youth cannabis consumption decreased in states where adult-use legalization had been in place for two years or more.
“Consistent with estimates from prior studies, there was little evidence that [adult-use laws] or MMLs encourage youth marijuana use,” the researchers said. “As more post-legalization data become available, researchers will be able to draw firmer conclusions about the relationship between [adult-use laws] and adolescent marijuana use.”
The study authors didn’t attempt to explain why youth might not be using marijuana more frequently in states that have legalized, but it’s a trend that doesn’t surprise advocates who have long reasoned that permitting sales in a regulated environment would detract from the illicit market and minimize youth access.
“This study provides additional evidence that legalizing and regulating cannabis does not result in increased rates of use among teens,” Matthew Schweich, deputy director of the Marijuana Policy Project, told Marijuana Moment. “In fact, it suggests that cannabis legalization laws might be decreasing teen use.”
“That makes sense because legal cannabis businesses are required to strictly check the IDs of their customers,” he said. “The unregulated market, which prohibitionists are effectively trying to sustain, lacks such protections.”
National Institute on Drug Abuse (NIDA) Director Nora Volkow also conceded in a recent interview that legalization has not led to increased youth use despite her prior fears.
Volkow said on Drug Policy Alliance* founder Ethan Nadelmann’s podcast that she was “expecting the use of marijuana among adolescents would go up” when states moved to legalize cannabis, but admitted that “overall, it hasn’t.” It was reform advocates like Nadelmann who were “right” about the impact of the policy change on youth, she admitted.
A federal report released in May also challenged the prohibitionist narrative that state-level marijuana legalization leads to increased youth use.
The US Department of Education’s National Center for Education Statistics also analyzed youth surveys of high school students from 2009 to 2019 and concluded that there’s been “no measurable difference” in the percentage of those in grades 9-12 who reported consuming cannabis at least once in the past 30 days.
In a separate, earlier analysis, the Centers for Disease Control and Prevention found that marijuana consumption among high school students declined during the peak years of state-legal adult-use cannabis legalization.
There was “no change” in the rate of current cannabis use among high school students from 2009-2019, the survey found. When analyzed using a quadratic change model, however, lifetime marijuana consumption decreased during that period.
A federally funded Monitoring the Future report released late last year found that cannabis consumption among adolescents “did not significantly change in any of the three grades for lifetime use, past 12-month use, past 30-day use and daily use from 2019-2020.”
Another study released by Colorado officials last year showed that youth cannabis consumption in the state “has not significantly changed since legalization” in 2012, though methods of consumption are diversifying.
An official with the White House Office of National Drug Control Policy’s National Marijuana Initiative went even further last year, admitting that, for reasons that are unclear, youth consumption of cannabis “is going down” in Colorado and other legalized states and that it’s “a good thing” even if “we don’t understand why.”
Past studies looking at teen use rates after legalization have found declines in consumption or a similar lack of evidence indicating there’s been an increase.
In 2019, for example, a study took data from Washington state and determined that declining youth marijuana consumption could be explained by replacing the illicit market with regulations or the “loss of novelty appeal among youths.” Another study from last year showed declining youth cannabis consumption in legalized states but didn’t suggest possible explanations.
Photograph via New York State
* DPA previously provided a restricted grant to The Influence Foundation, which operates Filter, to support a Drug War Journalism Diversity Fellowship.