Predicting alcohol and drug use in early adulthood: the role of internalizing and externalizing behavior problems in early adolescence.

Unique and interactive internalizing and externalizing behavior problems in adolescence were examined in relationship to drug and alcohol use in young adulthood. Results indicated that higher externalizing scores in adolescence predicted more alcohol use in young adulthood for both males and females and also predicted more marijuana and hard drug use for males. Lower internalizing scores were found to predict more marijuana and hard drug use in young adulthood for boys, but not for girls.