[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] Akershus Univ Hosp, Div Mental Hlth Serv, Lorenskog, Norway
[4] Univ Oslo, Inst Clin Med, Oslo, Norway
[5] Inland Norway Univ Appl Sci, Dept Publ Hlth, Elverum, Norway