[1] Univ Oulu, Dept Psychiat, Inst Clin Med, Oulu, Finland
[2] Univ Cambridge, Dept Psychiat, Cambridge, England
[3] Univ Helsinki, Dept Psychiat, Inst Clin Med, SF-00180 Helsinki, Finland
[4] Univ Oulu, Inst Hlth Sci, Dept Publ Hlth Sci, Oulu, Finland