Previous work shows long-term negative consequences of adolescent marijuana use, including addiction and escalation to harder drugs. However, our understanding of mechanisms leading to negative effects is limited. Recent data suggest that rates of marijuana use have been increasing rapidly among Black adolescents in contrast to slight increases among Whites. Hence negative consequences are increasingly a serious concern particularly for urban dwelling Blacks who often face other vulnerabilities that hinder their ability to successfully transition to adulthood. In this study we investigate the long-term course of substance use that adolescent onset marijuana use may set Black youth on and various mechanism that may explain this continuity, including criminal justice system involvement, drug dealing, and drug escalation.
We utilize data from the Woodlawn study, a prospective, community cohort study of urban Black youth followed from 1st grade (N=1242) to midlife. All children from the Woodlawn community neighborhood in Chicago were initially assessed by teachers and mothers. During adolescence, children and mothers were reassessed. Adult interviews were conducted at ages 32 and 42. Official criminal justice records were collected over time. We utilize regression analysis to predict midlife substance use outcomes that capture the 10 years between the young adult and midlife interviews. We test four mediators from young adulthood that may explain the long-term substance use continuity: having a drug arrest, self-reported drug dealing, drug dependence, and escalation to harder drugs.
Adjusted logistic regression models show that heavier adolescent marijuana users are over twice as likely as lighter/nonusers to use cocaine and/or heroin in midlife and almost twice as likely to meet criteria for substance abuse in midlife. Neither drug-related crime nor dependence explained these long-term associations. Instead, use of cocaine and/or heroin in young adulthood completely mediated these long-term effects.
Results suggest that adolescent marijuana use may set Black urban youth on a long-term trajectory of harder drug use (i.e., cocaine and heroin), which may continue into midlife and increase the risk of substance abuse. Findings point out the importance of interventions to decrease the risk of adolescent marijuana users transitioning to heavier drugs, particularly for those for whom early prevention is not effective or available. Further work must explore how decriminalization and legalization of marijuana decrease the link between marijuana and harder drugs thereby preventing some of the negative effects that plague vulnerable youth.