1. Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy
2. Department of Statistics, University of Bologna, Bologna, Italy
3. United Hospitals of Ancona and Polytechnic University of Marche, Psychiatric Clinic, Ancona, Italy
4. Department of Mental Health, Azienda USL Bologna, Bologna, Italy
5. Department of Mental Health, Azienda USL Trieste, Trieste, Italy