1 Department of Psychosomatic Medicine and Psychotherapy, Centre for Internal Medicine, University Medical Centre Hamburg-Eppendorf Hamburg, Hamburg, Germany.
2 Department of Psychosomatic Medicine and Psychotherapy, University Medical Hospital, Tübingen, Germany.
3 German Centre for Mental Health (DZPG), Tübingen, Germany.
4 Health Psychology, University of Leuven, Leuven, Belgium.
5 Department of Psychosomatic Medicine and Psychotherapy, Technical University of Munich, Munich, Germany.
6 German Centre for Mental Health (DZPG), Munich, Germany.