1. Faculty of Medicine, University of Oslo, Oslo, Norway
2. Division of Mental Health and Addiction, Oslo University Hospital Ullevaal, Nydalen, Oslo, Norway
3. Department of Behavioural Sciences in Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Blindern, Oslo, Norway
4. Department of Drug Abuse Research, Norwegian Institute of Public Health, Nydalen, Oslo, Norway
5. Lovisenberg University College, Oslo, Norway