1. Laboratory of Epidemiology and Social Psychiatry, `Mario Negri' Institute, Via Eritrea 62, 20157 Milan, Italy. Laboratory of Epidemiology and Social Psychiatry of the `Mario Negri' Institute, Milan, Italy.
2. Laboratory of Epidemiology and Social Psychiatry of the `Mario Negri' Institute, Milan, Italy.
3. Regione Lombardia, Assessorato alla Sanità, Milan, Italy.