1. Internal Medicine 1, Klinikum Saarbrücken, Winterberg 1, D-66119 Saarbrücken, Germany
2. Department of Psychosomatic Medicine & Psychotherapy, Technische Universität München, Ismaningerstraβe 22, D-81675 München, Germany
3. Day Clinic & Out Patient Department Pain Therapy, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
4. Department of Palliative Medicine, University Hospital Bonn, Center of Palliative Care, Malteser Hospital Seliger Gerhard Bonn/Rhein-Sieg, D-53127 Bonn, Germany
5. Department of Neurology, Technische Universität München, Ismaningerstraβe 22, D-81675 München, Germany