Demographic, individual, and interpersonal predictors of adolescent alcohol and marijuana use following treatment.

A vulnerability model of adolescent substance abuse treatment outcome provided the basis for selection of demographic, individual, interpersonal, and treatment factors to predict the follow-up use of alcohol and marijuana in a sample of adolescents (N = 225) with psychoactive substance use disorders. Pretreatment levels of sibling substance use and aftercare participation predicted alcohol and marijuana use during the first 6 months posttreatment. Pretreatment levels of deviant behavior also predicted the use of marijuana at 6-month follow-up. Peer substance use at intake and 6-month posttreatment both predicted substance use frequency outcomes at 12-month follow-up. Alcohol and marijuana use frequencies at 6-month follow-up also predicted continued use for these substances throughout the remainder of the 1st posttreatment year. Shorter treatment length and being male were risk factors for alcohol use during the 2nd half of the 1st posttreatment year. Elevated psychological substance dependence at 6-month follow-up was a unique risk factor for subsequent marijuana use. Findings support conceptual models that attempt to explain adolescent substance abuse treatment outcome in terms of relationships among demographic, individual, interpersonal, and treatment factors.