[1] Natl Publ Hlth Inst, Dept Mental Hlth & Alcohol Res, Helsinki 00251, Finland
[2] Univ Helsinki, Dept Forens Med, SF-00300 Helsinki, Finland
[3] Jarvenpaa Addict Hosp, A Clin Fdn, Helsinki, Finland
[4] Univ Helsinki, Res Unit Subst Abuse Med, SF-00300 Helsinki, Finland