[1] Innlandet Hosp Trust, Norwegian Natl Advisory Unit Concurrent Subst Abu, PB 104, N-2381 Brumunddal, Norway
[2] Univ Oslo, Norwegian Ctr Addict Res SERAF, Inst Clin Med, Oslo, Norway
[3] Innlandet Hosp Trust, Div Mental Hlth, PB 104, N-2381 Brumunddal, Norway
[4] Akershus Univ Hosp, Mental Hlth Serv, Lorenskog, Norway
[5] Univ Oslo, Inst Clin Med, Oslo, Norway
[6] Inland Norway Univ Appl Sci, Dept Publ Hlth, Elverum, Norway