This, from 2009, looks like an important study but I've never noticed it before - anyone know anything about it? I saw one brief comment from Dolphin that almost all the contributing studies are by CBT proponents, and a 2010 'General News' thread received no replies. Are chronic fatigue and chronic fatigue syndrome valid clinical entities across countries and healthcare settings? 2009 (full text pdf) Hickie I, Davenport T, Vernon SD, Nisenbaum R, Reeves WC, Hadzi-Pavlovic D, Lloyd A. Australian and New Zealand, Journal of Psychiatry; 43:25-35, 2009. It's a vast meta-analysis of symptom data on nearly 38,000 fatigued patients including 1,950 with CFS and was recently cited by van der Meer and Lloyd in their editorial critiquing the ICC to argue that: The study was supported by the CDC as part of the International Chronic Fatigue Syndrome Study Group that came up with the 2003 ('Ambiguities') revision of Fukuda. From a quick look it appears the majority of CFS cases were Fukuda-defined wiht most of the rest Oxford, and no Empiric. Google scholar lists only 10 citations of the paper, so maybe it isn't such a big deal.