“Marijuana use among youth may actually decline after legalization for recreational purposes,” the most recent study on the subject concludes. Laws that legalize recreational marijuana are typically followed by an 8% drop in reported recent marijuana use and a 9% decrease in the odds of frequent marijuana use among high schoolers. The same correlation couldn’t be observed in states where only medical marijuana is available.
The study, published in the medical journal JAMA Pediatrics on Monday, July 8, was authored by economists from the state universities of Montana, Oregon, Colorado and California.
“Policy makers are particularly concerned that legalization for either medicinal or recreational purposes will encourage marijuana use among youth,” the study says. This is a widespread fear; a majority of opponents of cannabis legalization fear that legal weed will lead to increased consumption by the young and impressionable. It would appear that the exact opposite is true.
Previous research on the subject showed that the link between cannabis legalization and rates of use is complex. Two distinct studies, in February 2017 then December 2018, reached opposite conclusions using different sources of data; both studies looked into cannabis use among eighth and tenth graders in Washington state, but one claims that usage rose slightly while the other estimates it fell. To avoid such biases, the most recent study used data collected by the Centers for Disease Control and Prevention.
“Because our study is based on more policy variation than prior work, we view our estimates as the most credible to date in the literature,” Mark Anderson, associate professor at Montana State University, told CNN. Unlike many other past studies, which were limited to one state, his work includes the entire country with data on about 1.4 million high school students.
Other research, for instance in the American Law and Economics Review or led by the Colorado state government, seems in line with Anderson’s results.
The Underlying Reasons
The decreased rate of marijuana use after legalization could be linked to a diminished “forbidden fruit” effect, the Drug Policy Alliance wagers. When an activity is seen as transgressive and rebellious, teenagers are more likely to partake in it, no matter how illegal it is.
Portugal, where cannabis is decriminalized, touts some of the lowest rates of cannabis use in the European Union, while marijuana was an endemic issue when it was still illegal. While Portuguese citizens could consume cannabis with no repercussion, 2015 studies found that only 5.1% of young Portuguese people consumed marijuana in the past year, while 32.2% of young Americans consumed cannabis in the same time frame.
Earlier this year, Washington State University associate professor Janessa Graves put forth the idea that the difference in cannabis use among the youth, when it is legal, could be linked to employment. “Post-legalization, 4.8% of non-working eighth graders reported using pot within the last 30 days, while 20.8% of their working peers did,” she wrote in a paper on the subject. It concluded that only one group of teenagers used marijuana more often after retail sales were legalized in Washington than they did before—high school seniors who work 11 or more hours per week. "Kids who work more often use substances, that's not a shock," Graves said, as a work environment is a point of contact with adults who aren’t their parents or educators, thus potential plugs for drugs.
However, the most important explanation is perhaps that legal cannabis is regulated by the government and sold by professionals rather than drug dealers. Although there are still drug dealers, a significant portion of their previous clientele is diverted towards legal dispensaries after legalization, reducing their income and clout. “It is more difficult for teenagers to obtain marijuana as drug dealers are replaced by licensed dispensaries that require proof of age,” Anderson and his co-authors concluded.
