Subjects were 78 residents of a residential drug treatment program in St. Petersburg, Fla., and 79 residents of a shelter for runaways in Tampa, Fla. The adolescents ranged from 12 to 18 years of age, with an average age of 15. Subjects completed a questionnaire that included the Rational Behavior Inventory (RBI); demographic variables; and questions concerning a variety of delinquent activities, including running away and drug abuse. Specific belief systems were found to be differentially associated with each disorder. Two beliefs -- avoidance and control of emotions -- had moderate predictive value for running away. Beliefs more strongly predicting the frequency of drug use were catastrophizing, approval, and blame and punishment. In addition, two dimensions of beliefs were associated with drug abuse among adolescent males but not among females. Research recommendations, data table, and 71 references. (Author abstract modified)