[1] Hannover Med Sch, Dept Clin Psychiat & Psychotherapy, D-30625 Hannover, Germany
[2] Univ Bremen, Inst Psychol & Cognit Res, D-28359 Bremen, Germany
[3] Univ Essen Gesamthsch, Dept Med Psychol, D-45122 Essen, Germany
[4] Univ Essen Gesamthsch, Dept Med, D-45122 Essen, Germany
[5] Hannover Med Sch, Dept Nucl Med, D-30625 Hannover, Germany
[6] Swiss Fed Inst Technol, Div Psychol & Behav Immunobiol, Inst Behav Sci, CH-8092 Zurich, Switzerland