In a research letter published on July 8, 2019 in JAMA Pediatrics (a monthly peer-reviewed medical journal published by the American Medical Association), Drs. Mark Anderson, Benjamin Hansen, and Daniel I. Rees reported that teen marijuana use might decrease in response to recreational legalization. If true, this would take a potent arrow out of the quiver of the anti-legalization movement.

The researchers used data from the Youth Risk Behavior Surveys (YRBS) collected between 1993 and 2017. This included data from 27 states and the District of Columbia before and after the legalization of medical marijuana, and from seven states before and after the legalization of recreational marijuana. The YRBS is a survey administered every other year to high school students which allows government agencies and researchers to track youth behaviors.

Upon review of the data, the researchers found no statistically significant change in the odds of teen marijuana use or frequent teen marijuana use (use at least 10 times in the past 30 days) upon the legalization of medical marijuana. The researchers did, however, find a statistically significant decrease of 8% in the odds of teen marijuana use and 9% in the odds of frequent teen marijuana use upon the legalization of recreational marijuana.

These findings would appear counterintuitive, and certainly run contrary to the narrative advanced by opponents of legalization. The researchers suggested that perhaps it becomes more difficult for teenagers to purchase marijuana in legalized states because the black market shrinks and recreational dispensaries require strict proof of age. But whatever the causation, if other research confirms a decrease in teen marijuana usage upon recreational legalization, that could significantly change the legalization calculus for legislators and voters throughout the country. We will continue to monitor the research and report on any significant developments.