[1] Ruhr Univ Bochum, Dept Clin Psychol & Psychotherapy, D-44780 Bochum, Germany
[2] Univ Freiburg, Dept Clin Psychol & Psychotherapy, Freiburg, Germany
[3] Univ Dusseldorf, Dept Clin Psychol, Dusseldorf, Germany
[4] Univ Clin Hamburg, Ctr Internal Med & Dermatol, German Ctr Competence Hlth Serv Res Dermatol, Hamburg, Germany
[5] Univ Munster, Dept Psychiat, Munster, Germany
[6] Ruhr Univ Bochum, Dept Psychosomat Med & Psychotherapy, D-44780 Bochum, Germany