[1] Univ Med Ctr Freiburg, Dept Psychiat & Psychotherapy, Clin Epidemiol Sect, D-79104 Freiburg, Germany
[2] Univ Med Ctr Hamburg Eppendorf, Ctr Psychosocial Med, Inst & Policlin Med Psychol, Hamburg, Germany
[3] Palo Alto Med Fdn Res Inst, Dept Hlth Serv Res, Palo Alto, CA USA
[4] Univ Calif Los Angeles, Dept Med, Div Gen Internal Med, Los Angeles, CA 90024 USA
[5] Univ Calif Los Angeles, Dept Med, Hlth Serv Res, Los Angeles, CA 90024 USA
[6] Univ Med Ctr Freiburg, Dept Psychiat & Psychotherapy, Hlth Serv Res, D-79104 Freiburg, Germany