[1] Radboud Univ Nijmegen, Nijmegen Med Ctr, Expert Ctr Chron Fatigue, NL-6525 EC Nijmegen, Netherlands
[2] Radboud Univ Nijmegen, Nijmegen Med Ctr, Dept Internal Med, Nijmegen, Netherlands
[3] Barts & London Queen Marys Sch Med & Dent, Dept Med Psychol, London, England