This study has two major aims; (a) to determine the efficacy of a drug dependence treatment program which includes family therapy, contrasted with a similar program which does not include family therapy; and, (b) to identify patterns of interaction which characterize families of heroin addicts, with hope that these will generate hypotheses for future clinical investigation and treatment. The study will employ 100 families. Twenty-five of these will be the families of medical patients and will compose the control group. The remaining 75 will be families in which at least one member is a heroin addict. All the addicts will be engaged in a multi-modal treatment program including methadone and frequent urine tests, and 50 of them will attend ten weekly family therapy sessions. The 25 addict families who do not receive family therapy will be required to attend weekly movie sessions together as a control for weekly family gatherings at the clinic. All 100 families, including controls, will participate in two videotaped interaction sessions, spaced three months apart, which will be rated and clinically assessed in order to identify the patterns characterizing families of drug addicts.