Does legalization boost teen marijuana use?

• Author: Sullum, Jacob
• Position: DRUGS

WHEN THE NATIONAL SurveyonDrug Use and Health (NSDUH) indicated that marijuana use by teenagers in Colorado rose after the state legalized the drug for recreational use in 2012, prohibitionists trumpeted the results, even though the change was not statistically significant. Drug warriors were notably quieter when subsequent NSDUH data indicated that adolescent consumption in Colorado fell after state-licensed marijuana stores began serving the recreational market.

That change was not statistically significant either, underlining the uncertainty about the impact of legalization on underage consumption. It is plausible that legalization would increase adolescent use by making marijuana more socially acceptable (although probably not cooler) or by making it available from legal buyers 21 or older. But so far there is little evidence that is happening.

The Colorado Department of Public Health and Environment says cannabis consumption by teenagers in the state "has not changed since legalization either in terms of the number of people using or the frequency of use among users." That conclusion is based on data from NSDUH and the Healthy Kids Colorado Survey, which has a much larger sample of Colorado teenagers.

A study published in the February 2017 issue of JAMA Pediatrics covered yet another survey, the Monitoring the Future Study. University of California, Davis, epidemiologist Magdalena Cerda and her colleagues looked at past-month marijuana consumption among eighth-, 10th-, and 12th-graders in the three years preceding legalization (2010-12) and the three years following it (2013-15). They compared trends in Colorado and Washington, where...