1. Department of Psychosomatic Medicine, Rehazentrum Oberharz, Clausthal-Zellerfeld, Germany
2. Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Medicine, KRH Klinikum Nordstadt, Hannover, Germany
3. Department of Anesthesiology and Intensive Care Medicine, Pain Clinic, Hannover Medical School, Hannover, Germany
4. Department of Psychology, University of Utah, Salt Lake City, UT, USA
5. Department of Economics and Social Sciences, University of Applied Science Nordhausen, Nordhausen, Germany