Substance abuse touches around a quarter of psychiatric patients, which brings up various therapeutic problems. Literature shows us that between the "parallel", "series" and "integrated" approaches, it is the integrated approach which proves to be the most effective in terms of reducing symptoms, hospitalisations and criminality. An improvement in the patients' quality of life can also be observed. The integrated approach is developed by a team of in-patient and out-patient workers, whose job is to identify and evaluate clinically the motivation and the psychological and social functioning of the patients, and to propose suitable treatments according to the pathology and context of each case. A designated "case manager" guarantees the long term therapeutic project for each patient.