Comment on: Chronic fatigue syndrome: prevalence and outcome. [BMJ. 1994]
Editor,-The struggle over myalgic encephalomyelitis and the chronic fatigue syndrome is not, as S M Lawrie and A J Pelosi suggest, whether they are physical or mental illnesses. Both sides in this debate accept that most illnesses combine organic and psychological factors. The struggle is about methodology and definition and, in particular, how different methodologies and definitions inevitably lead to different findings on the degree to which depression is a perpetuating agent in these conditions.
One side favours studying the chronic fatigue syndrome as a single entity, arguing that there is insufficient knowledge at present to differentiate between different chronic fatigue syndromes. This side prefers Sharpe et al’s broad definition of the syndrome, which includes depressive illness, anxiety disorders, and the hyperventilation syndrome.2 Unsurprisingly, studies that use these criteria find higher levels of depression ) or “psychosocial disorders”-yet another woolly term).
The other side argues that there is sufficient knowledge to distinguish specific chronic fatigue syndromes, particularly the much studied myalgic encephalomyelitis, and that it must be better science in these cases to study such syndromes in their own right. Furthermore, it argues that the study groups used in research based on broadbrush criteria will have been so aetiologically heterogeneous as to invalidate the findings. This side, which includes the national patient organisations, equates myalgic encephalomyelitis with Holmes et als tighter definition of the chronic fatigue syndrome, which focuses more on organic symptoms and, again unsurprisingly, finds lower levels of depression similar to those found in patients with cancer and multiple sclerosis-that is, the levels that might be predicted in any chronic illness.3
You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540172/pdf/bmj00440-0054a.pdf
Source: Anderson N. Chronic fatigue syndrome. …and study them separately. BMJ. 1994 May 14;308(6939):1298. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540172/