1. Department of R&D in Mental Health; Akershus University Hospital; Lørenskog Norway
2. Norwegian Center for Addiction Research; University of Oslo; Oslo Norway
3. Department of Addiction Medicine; Haukeland University Hospital; Bergen Norway
4. The University of Bergen; Bergen Norway
5. Institute of Clinical Medicine; Campus Ahus; University of Oslo; Blindern Norway
6. Health Services Research Unit; Akershus University Hospital; Lørenskog Norway
7. Department of Addiction Medicine; Oslo University Hospital; Oslo Norway