1. Department of Research and Development in Mental Health, Akershus University Hospital, Lørenskog, Norway
2. Norwegian Center for Addiction Research, University of Oslo, Oslo, Norway
3. Institute of Clinical Medicine, Campus Ahus, University of Oslo, Oslo, Norway
4. Health Services Research Unit, Akershus University Hospital, Lørenskog, Norway
5. Department of Addiction Medicine, Haukeland University Hospital, Bergen, Norway
6. Faculty of Medicine and Odonthology, The University of Bergen, Bergen, Norway
7. Department of Addiction Medicine, Oslo University Hospital, Oslo, Norway
8. Vestfold Hospital Trust, Toensberg, Norway