The frequency of alcohol and drug use, abuse and severity of dependence, and personality and family characteristics in 280 female and male hospitalized adolescents in treatment for chemical dependence and 120 middle class adolescents were examined. A MANOVA showed that parents' drug and alcohol use was a main effect, increasing frequency of use and severity of dependence upon alcohol and drugs in both groups of adolescents. Sexual and physical abuse studied in the patient group also functioned as a main effect. Patients reported significantly less family interests, and participation in intellectual, cultural and social activities, but more control than the comparison group. It was concluded 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.