1. Department of Psychosomatic Medicine and Psychotherapy, University Hospital Magdeburg, 39120 Magdeburg, Germany
2. German Center for Mental Health (DZPG), Site Jena-Magdeburg-Halle, 07745 Jena, Germany
3. Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tuebingen, 72076 Tuebingen, Germany
4. Institute for Medical Biometrics and Clinical Epidemiology, University Hospital Tuebingen, 72076 Tuebingen, Germany
5. Klinikum Stuttgart, 70174 Stuttgart, Germany
6. Department of Psychosomatic Medicine and Psychotherapy, Klinikum Rechts der Isar, Technical University of Munich, 80333 Munich, Germany
7. Institute for Medical Epidemiology, Biometrics and Informatics, Interdisciplinary Center for Health Sciences, Medical School, Martin-Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
8. Public Health Department of Stuttgart, 70176 Stuttgart, Germany