1. Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway;
2. Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway;
3. Norwegian Advisory Unit on Complex Symptom Disorders, St. University Hospital, Trondheim University Hospital, Trondheim, Norway;
4. Hysnes Rehabilitation Center, St. University Hospital, Trondheim, Norway;
5. Department of Mental Health, Faculty of Medicine and Health Science, Norwegian University of Science and Technology, Trondheim, Norway;
6. Department of Physical Medicine and Rehabilitation, St. University Hospital, Trondheim University Hospital, Trondheim, Norway