The typology includes four main categories: 1) traumatic drug addiction, resulting from a serious trauma; 2) drug addiction from actual neuroses; 3) transitional drug addiction, involving interactions of psychotic and neurotic components; and 4) sociopathic drug addiction, which is common in adolescents who act out psychic conflicts. Researchers assigned individuals to the four categories based on written information provided independently by therapists at the Albedo Center in Rome. The analysis of the addicts and their families indicated that families of drug addicts cannot be seen as homogeneous systems. The distinctions are sometimes useful in choosing family therapies. In addition, a combination of family therapy and other therapeutic approaches may be preferable in some situations. Data tables and 29 references.