1. The Norwegian Centre for Addiction Research, The University of Oslo, Oslo, Norway;
2. Department of Circulation and Medical Imaging, The Norwegian University of Science and Technology, Trondheim, Norway;
3. Department of Anesthesiology and Critical Care, Oslo University Hospital, Oslo, Norway;
4. Department of Acute Medicine, Oslo University Hospital, Oslo, Norway;
5. St. Olav’s Hospital, University Hospital of Trondheim, Trondheim, Norway;
6. Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway