1. Clinic for Psychosomatic Medicine and Psychotherapy, LVR-University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
2. Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany.
3. Department of Experimental and Clinical Medicine, University of Florence, Firenze, Italy.
4. TIME-Tübingen Institute for Medical Education, Medical Faculty Tübingen, Tübingen, Germany.
5. West German Center for Organ Transplantation, University Hospital Essen, Essen, Germany.