There were 280 female and male adolescents in the hospitalized sample and 120 in the comparison group, Various instruments were used to measure alcohol and drug dependence, drug use, intellectual and neuropsychological functioning, personality characteristics, family interactions and the climate of family life, and physical and sexual abuse experienced by the patients. The study found that parents' drug and alcohol use was a primary factor in the frequency of drug and alcohol use and the severity of dependence upon alcohol and drugs in both groups of adolescents. Sexual and physical abuse of those in the patient group was also a primary factor. Patients reported significantly less family interests and participation in intellectual, cultural, and social activities than the families of nonpatients; however, there was more control in the families of patients. The study concludes that adolescent alcohol and other drug abuse is part of a biopsychosocial syndrome of problem behavior which includes the problem behavior of parents and the interacting family unit. 4 tables and 42 references