[1] Univ Hosp North Norway, Div Mental Hlth & Subst Abuse, POB 6124, N-9291 Tromso, Norway
[2] UiT Arctic Univ Norway, Fac Hlth Sci, Dept Clin Med, Tromso, Norway
[3] UiT Arctic Univ Norway, Fac Hlth Sci, Dept Psychol, Tromso, Norway
[4] Norwegian Inst Publ Hlth, Oslo, Norway
[5] Norwegian Natl Advisory Unit Concurrent Subst Abu, Hamar, Norway