(4) Adolescent drug use—The effect of prescribed therapist behaviors on adolescent drug use was complex. Across time, as would be expected, joining decreased, and restructuring increased. Smaller declines in joining and larger increases in restructuring predicted significantly less adolescent drug use at the 12-month follow-up. That is, therapists who were high in joining in early sessions and remained so throughout treatment were associated with “better” adolescent drug-use outcomes. Therapists whose attempts to restructure maladaptive family interactions increased the most during the course of treatment were also associated with “better” adolescent drug-use outcomes. Thus, therapists who failed to implement sufficient numbers of restructuring interventions were less able to affect the youths’ drug use.