Youth Marijuana Use Following Commercial Sales of Legal Recreational Marijuana

Missouri recently approved medical marijuana. Based on experience in other states, proposals to legalize recreational marijuana in Missouri will soon follow. The Journal of the American Medical Association Pediatrics recently published a flawed research letter purporting to show that past-month teen marijuana use declined after states legalized recreational marijuana.¹ This questionable study is being publicized by Missouri press.

Although the authors did not describe their methods in enough detail to check their work, a few shortcomings stand out. Anderson et al. misled readers by: asserting they used seven states’ data after “adoption” of recreational marijuana laws (RML); neglecting to report the actual figures for youth use; and omitting the trends in use in states without legal marijuana.

The authors used data from the biennial Youth Risk Behavior Surveys (YRBS).² However, the latest survey, conducted in 2017, occurred after commercial recreational sales began in only two RML states, not seven as the authors claim. Of the four states that legalized in 2012–2014 (Oregon, Washington, Alaska and Colorado), two states (Washington and Oregon) do not submit data to the YRBS. Four states (California, Nevada, Maine, and Massachusetts) voted to legalize in 2016, but none of them opened licensed recreational marijuana shops prior to January 1, 2017. In fact, California and Massachusetts did not open shops until 2018. Maine and the District of Columbia, which voted to legalize in 2014, do not have stores selling recreational marijuana yet.

The distinction between the year that the law passed versus the year when pot shops opened is critical because Anderson et al. disingenuously concluded that youth use decreased because “it is more difficult for teenagers to obtain marijuana as drug dealers are replaced by licensed dispensaries that require proof of age.” That conclusion is erroneous because the final year of data collection is prior to the opening of these ethical, age-verifying stores.

To judge the effect of RMLs, we are left with only two early legalizer states that submitted data to the YRBS and had a functioning commercial recreational marijuana market prior to 2017. Colorado did not submit complete data in 2013 and 2015. Moreover, Denver, its largest city, hasn’t submitted a report since 1995. Using the last complete year (2011) as a baseline and the most recent year (2017) as the final year, we find that youth use (ages 12–17) in Alaska increased from 21.2% to 21.5% (1.4% increase) and in Colorado decreased from 22.0% to 19.6% (10.9% decrease). Meanwhile, median youth use in the United States as a whole decreased from 21.1% to 18.6% (11.8% decrease). The two states with RML fared worse than the nation as a whole.

To get data from the other early legalizers, we have to turn to the National Survey on Drug Use and Health³ (NSDUH). During the same time period, the NSDUH showed a nationwide decline in youth use of 14.4%, while Washington only declined by 5.2% and Oregon increased by 5.0%. Once again, RML states showed youth use trends worse than the national average.

The news from Oregon is particularly disturbing, and it might be a harbinger of the future, having a burgeoning commercial market offering cheap prices.⁴ Using NSDUH data from 2011–2012 and 2016–2017, Oregon’s past month marijuana use among 18- to 25-year-olds increased more than twice the national average (28.4% vs. 13.6%).

The legalization of commercial sales of recreational marijuana does not reduce past month use in teenagers compared to other states. In fact, the data show a trend towards worse outcomes in states that have legalized. We call for further statistical analysis by unbiased experts who want to elucidate rather than obfuscate the trends in marijuana use.

References