Past 15-Year Trends in Adolescent Marijuana Use

We are currently in a moment of significant secular change in terms of marijuana policy, and these policy changes have implications for adolescent marijuana use. Importantly, adolescence is the period during which most people use marijuana for the first time, and national data show that, in 2013, 23% of high school students reported past-month use of marijuana, and 40.1% reported lifetime use. Moving forward, it will be important to closely monitor changes in adolescent marijuana use to assess how policy impacts patterns of use and to respond appropriately. Therefore, the purpose of the study is to examine the prevalence and trends in reported marijuana use from 1999-2013, overall and by race/ethnicity and sex. Data come from the national Youth Risk Behavior Survey, a nationally representative school-based survey of 9th-12th graders in the US. We examined the statistical significant of trends in: any lifetime use, repeated lifetime use, any past 30-day use, repeated past 30-day use, and early use (ie, before age 13). We calculated the prevalence of and 95% CI for current marijuana use overall and by sex, within each race/ethnic group. We also tested the statistical significance of linear and quadratic trends to assess trends over time. Although there has been a downward linear trend in marijuana use since 1999, there has been a small uptick in use since 2009. For all race/ethnicity groups, the gender gap in use has gotten smaller over time. Implications for policy will be discussed.