Session: Long-Term Consequences of Marijuana Use from Childhood through Adulthood (Society for Prevention Research 22nd Annual Meeting)

Introduction:With the trend toward decriminalization and even legalization of marijuana in several states in the U.S., it is important to delineate consequences of use, especially early-onset use. This symposium includes three presentations based on longitudinal studies that followed youth from childhood or early adolescence into adulthood. We examine outcomes in several domains: physical health, mental health, educational achievement, socioeconomic status, and social roles.

Methods and Results: Presentation 1 examines physical health outcomes in young adulthood (age 35) of regular (monthly) marijuana use from early adolescence into emerging adulthood and of frequent use in emerging and young adulthood for a sample of Black and White young men. The findings indicate no significant effects of persistent or frequent marijuana use on negative health outcomes by age 35 for either race. Presentation 2 examines mental health outcomes at age 33 of persistent and early onset regular (4 times per week) marijuana use in a sample of males and females followed since elementary school. The findings indicate that persistent regular marijuana use was positively related to generalized anxiety disorder, alcohol use disorder, nicotine dependence, and other drug use disorders at age 33, even after controlling for confounding factors. Presentation 3 includes a sample of Black males and females followed from the first grade through age 42. Using propensity score matching to adjust for confounding factors, the results indicate that heavy marijuana use by age 16 had long-term negative consequences at midlife on social roles, socioeconomic status, and drug problems. Further, marijuana use and educational attainment in adulthood mediated these effects.

Conclusions: Together, the findings from these three studies suggest that early-onset and persistent marijuana use predicts negative mental health, social role, and socioeconomic outcomes but not physical health problems in adulthood. Therefore, interventions focusing on preventing early-onset marijuana use should highlight mental health and social role attainment consequences, which will probably have greater salience for young people than later physical health problems. Besides prevention programs designed specifically for marijuana use, interventions might want to directly target negative outcomes of use, such as educational achievement and anxiety symptoms, which will help to reduce the negative impact of marijuana use. The Discussant, who is a Federal employee, will discuss the importance of examining the effects of marijuana use over time and of identifying developmental, race, and gender appropriate targets for prevention. He will also highlight the implications of these findings for public policy.