Long-term consequences of adolescent cannabis use: Examining intermediary processes

Background: In the United States, perceptions of marijuana’s acceptability are at an all-time high, risk perceptions among youth are low, and rates are rising among Black youth. Thus, it is imperative to increase the understanding of long-term effects of adolescent marijuana use and ways to mitigate adverse consequences. Objectives: To identify the midlife consequences of heavy adolescent marijuana use and the mechanisms driving effects among a Black, urban population. Methods: This study analyzed the propensity score-matched prospective data from the Woodlawn Study, a community cohort study of urban Black youth followed from ages 6–42. After matching the 165 adolescents who used marijuana heavily to 165 non-heavy/nonusers on background confounders to reduce selection effects (64.5% male), we tested the association of heavy marijuana use by age 16 with social, economic, and physical and psychological health outcomes in midlife and the ability of adult drug trajectories (marijuana, cocaine, and heroin use from ages 17–42) and school dropout to mediate effects. Results: Heavy adolescent marijuana use was associated with an increased risk of being poor and of being unmarried in midlife. Marijuana use also predicted lower income and greater anxious mood in midlife. Both adult drug use trajectories and school dropout significantly mediated socioeconomic effects but not marital or anxious mood outcomes. Conclusion: Heavy adolescent marijuana use seems to set Black, urban youth on a long-term trajectory of disadvantage that persists into midlife. It is critical to interrupt this long-term disadvantage through the prevention of heavy adolescent marijuana use, long-term marijuana and other drug use, and school dropout.