1. Department of Clinical and Biomedical Sciences: Barwon Health, University of Melbourne, PO Box 281, Geelong, Vic., 3220, Australia
2. Department of Education and Health Promotion, University of Bergen, Norway
3. King's College London (Institute of Psychiatry), London, UK
4. Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway
5. Clinic of Child and Adolescent Mental Health Services, Haukeland University Hospital, Bergen, Norway
6. Norwegian Institute of Public Health, Oslo, Norway