[1] Psychiat Serv Thurgovia, Div Subst Use Disorders, Psychiat Clin, Munsterlingen, Switzerland
[2] Univ Basel, Psychiat Clin, Basel, Switzerland
[3] ZOPA, Outpatient Addict Treatment, Zug, Switzerland
[4] Psychiat Baselland, Liestal, Switzerland
[5] Arud Ctr Addict Med, Zurich, Switzerland
[6] Univ British Columbia, Inst Mental Hlth, Dept Psychiat, Vancouver, BC, Canada