In this article the authors propose: 1) a typology of drug addiction cases consisting of four main classes: A. traumatic drug addiction, B. drug addiction from actual neuroses, C. transitional drug addiction, and D. sociopathic drug addiction; 2) a clinical study (with 18 months of follow-up data) involving 131 heroin addicts mostly treated with structural or counterparadoxical family therapy in the same psychotherapy center and in the same year; and 3) some preliminary conclusions emerging from an examination of the four-class typology with respect to the effectiveness of family therapy interventions. If, for example, structural family therapy techniques seem more suitable in type-B cases (similar to cases described by Haley in his Leaving Home), the counterparadoxical techniques are likely to be more effective in type-C cases (similar to the anorectics described by Selvini-Palazzoli).