1. Department of Child Psychiatry; University of Turku; Turku Finland
2. Nordic School of Public Health; Gothenburg Sweden
3. National Institute for Health and Welfare; Helsinki Finland
4. Department of Psychiatry; Columbia University College of Physicians and Surgeons; New York State Psychiatric Institute; New York NY USA
5. Department of Epidemiology; Columbia University; Mailman School of Public Health; New York NY USA
6. Department of Child Psychiatry; Turku University Hospital; Turku Finland
7. Regional Centre for Child and Youth Mental Health and Child Welfare; University of Tromsø; Tromsø Norway