[1] Johns Hopkins Univ, Dept Med, Sch Med, Johns Hopkins Bayview Med Ctr, Baltimore, MD 21224 USA
[2] McGill Univ, Dept Psychiat, Montreal, PQ, Canada
[3] Sir Mortimer B Davis Jewish Hosp, Montreal, PQ H3T 1E2, Canada
[4] Univ Penn, Sch Med, Dept Psychiat, Philadelphia, PA 19104 USA
[5] Univ Groningen, Interdisciplinary Ctr Psychiat Epidemiol, Dept Psychiat, Univ Med Ctr Groningen, Groningen, Netherlands
[6] Univ Groningen, Interdisciplinary Ctr Psychiat Epidemiol, Dept Internal Med, Univ Med Ctr Groningen, Groningen, Netherlands
[7] Tilburg Univ, CoRPS Ctr Res Psychol Somat Dis, Dept Med Psychol, NL-5000 LE Tilburg, Netherlands