1. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
2. Department of Psychology, University of California-Riverside, Riverside, CA 92521, USA
3. Department of Clinical Psychology, Faculty of Social Sciences, Utrecht University, Utrecht, the Netherlands
4. Department of Biosciences, Viikki Biocenter, University of Helsinki, Helsinki, Finland
5. Department of Health, National Institute for Health and Welfare, Helsinki, Finland