Adolescent self-control predicts joint trajectories of marijuana use and depressive mood into young adulthood among urban African Americans and Puerto Ricans.

Previous studies have identified an association between depressive mood and marijuana use. We examined adolescent self-control as a predictor of membership in joint developmental trajectories of depressive mood and marijuana use from adolescence to young adulthood. Urban African Americans and Puerto Ricans (N = 838) were sampled when participants were on average 14, 19, 24, and 29 years old. Using growth mixture modeling, four joint trajectory groups of depressive mood and marijuana use were established: low marijuana use/low depressive mood, low marijuana use/intermediate depressive mood, high marijuana use/low depressive mood, and high marijuana use/high depressive mood. Weighted logistic regression analysis showed that self-control at age 14 distinguished the high marijuana use/high depressive mood group and the low marijuana use/low depressive mood group from each of the other groups. Findings show that the co-occurrence of high levels of marijuana use and depressive mood from adolescence into young adulthood is predicted by low levels of self-control in adolescence. On the other hand, high selfcontrol is associated with low marijuana use and low levels of depression over time. Thus, while deficits in self-control in adolescence constitute a significant risk for maladjustment over time, high self-control exerts a protective factor with regard to marijuana use and depressive mood into young adulthood.