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This paper presents a close analysis of a large published cohort trial into predictors (risk factors) for developing a fatigue syndrome or mood disorder following either infectious mononucleosis or an upper respiratory tract infection – White et al. *
Critically, in addition to utilizing broad based definitions of ME/CFS, such as the Oxford and CDC CFS criteria, White et al also utilize a further definition, Empirical Fatigue Syndrome, which excludes current psychiatric illness.
This provides important additional insights into the results, leading to conclusions which are materially different to those that the author draws, in relation to the inherent validity of broad based definitions of CFS and in relation to the significance of deconditioning as a perpetuating factor in this illness.
• Examination of the data shows that the highest risk factor for developing a non-psychiatrically defined Fatigue Syndrome (i.e. Empirical Fatigue Syndrome), even 6 months later, is documented clinical evidence of viral infection (infectious mononucleosis), not previous psychiatric morbidity.
• Furthermore under the Empirical definition, no significant correlation exists between bed rest at onset and subsequent development of a fatigue syndrome; this suggests that deconditioning is not an important perpetuating factor under this definition.
• Conversely, wider definitions of ME/CFS that do not exclude individuals with psychological/psychiatric reasons for their fatigue (such as the Oxford and CDC criteria):
• Reduce the importance of clinical factors (infectious mononucleosis)
• And increase the importance of factors such as GP attendance in year before onset, mood disorder at 2 months, and past psychiatric illness, which are consistent predictors of subsequent mood disorder quite independently of the existence or otherwise of a fatigue syndrome.
This analysis and the original data in the White et al. paper strongly calls into question the validity of broad based definitions of ME/CFS, such as the Oxford (and to lesser extent CDC) criteria. [bolding ours]
This is in large part due to the clear inclusion within such criteria of significant numbers of patients with primarily mood disorder/psychiatric illness in addition to those with ME/CFS.
Source: Bulletin of the IACFS/ME, Summer 2010;18(2):44-81, Sampson DP, et al. [Email: email@example.com]
* “Predictions and associations of fatigue syndromes and mood disorders that occur after infectious mononucleosis” http://www.ncbi.nlm.nih.gov/pubmed/11747919 Lancet, Dec 2001