Marijuana Legalization Doesn’t Increase Youth Use—Any Lessons for the Vaping Debate?

    Youth use of controlled substances is often deployed as a bargaining chip in drug policy debates. When it comes to cannabis, legalization laws are smeared for allegedly encouraging youth use⁠—but scientific evidence, including a review published this week, suggests otherwise.

    This principle has implications elsewhere. For example, the increasing availability of vaping products has been attacked by the US Food and Drug Administration and other vaping skeptics for spurring a teen vaping “epidemic.” But some research suggests that minimum legal sale age (MLSA) laws intended to reign in teen vaping have the unintended outcome of increasing teen smoking.

    A research letter published July 8 in the Journal of American Medical Association (JAMA) Pediatrics reviewed data on cannabis use amongst high school students from roughly the past two decades—a time-span that captures rates before and after marijuana legalization laws began spreading across the US. The researchers reported that there was no indication that legalization—currently embraced by 11 states plus Washington, DC, for recreational use, and by a total of 33 states for medical use—increased overall youth use between 1993 and 2017.

    The report notes that marijuana use amongst some teens may have increased after legalization, though researchers have found contradictory data. For example, eighth and 10th graders used marijuana more after Washington State’s recreational markets opened in 2014, according to a 2017 study that used national Monitoring the Future data; but researchers utilizing the Washington Healthy Youth Survey in a 2018 study found that recreational marijuana use among teens in those same grades fell.

    The JAMA Pediatrics research letter made findings similar to that 2018 study: that teen use might actually fall after recreational legalization. They suggest that this “may be because it is more difficult for teenagers to get marijuana if drug dealers are replaced by licensed dispensaries that require proof of age.”

    Similarly, clamping down on the availability of vapes may boost cigarette smoking amongst teens. This was suggested by researchers in a study published in January 2019 in the Wiley journal Health Economics. Using data from the Youth Risk Behavior Surveillance System for the years 2005 through 2015, they found that youth cigarette smoking increased in MLSA states by 7 percent relative to the two states without such laws during the time period studied—Michigan and Pennsylvania. Additionally, regular and heavy smoking amongst teens increased by 18 percent in MLSA states, relative to the baseline mean of the control states.  

    The Health Economics study notes that this turn by youth in vaping-age-restricted jurisdictions towards cigarettes, which have similar age restrictions, may be “counterintuitive.” But the authors explain that the “relative costs of accessing e-cigarettes (relative to cigarettes)” increases once the restrictions become leveled and that, given the entrenched history of cigarette use, teens seeking cigarettes already have “alternative ways to bypass the purchase restrictions,” like throughbumming’ or borrowing from a friend or adult.” 

    If e-cigarettes are only 5% as harmful as traditional cigarettes,” wrote the researchers,” then e-cigarette MLSA laws leading to increased smoking may cause greater harm than benefits.” 

    Photograph of a teenage girl smoking marijuana near Leakey, Texas; by Marc St. Gil, via Wikimedia Commons

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