1. Department of Public Health, The Hjelt Institute, University of Helsinki, P.O. Box 41, Mannerheimintie 172, 00014 Helsinki, Finland
2. Department of Health Sciences, University of Jyväskylä P.O. Box 35, 40014 Jyväskylä, Finland
3. Institute for Molecular Medicine, University of Helsinki, P.O. Box 21, Tukholmankatu 8, 00014 Helsinki, Finland
4. Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, P.O. Box 30, 00271 Helsinki, Finland