588

Journal of the Royal Society of Medicine Volume 85 September 1992

Chronic fatigue syndrome and heterogeneity One thing which hampers medical research is a frustrating tendency for researchers to conclude that heterogeneous groups are homogeneous. Several examples can be cited including research into sudden infant death syndrome.'In his editorial on' chronic fatigue syndrome (CFS) Wessely (AprI 1992' JRSM, p 189) asserts that previous views suggesting CFS to be simply a form of somatized aepression are no longer tenable' because of o'ne 'published and one unpublished study shiowing biological differences from major depression. This view is just as untenable as the notion that all CFS is depression. Surely the most likely explanation-' is that CFS represents a heterogeneous group. The notion that one or two positive findings exclude all' other explanations is a dangerous one. Aside from the fact that it negates the possibility of heterogeneity it may have a tendency to narrow thinking on the subject, and this is, after all, the food for medical research. B WRIGHT Meanwbod Park Hospital, Tongue Lane. Leeds LS6

Fluctuations in perceived energy and mood among patients with chronic fatigue syndrome I find it surprising that Wood et al. (April 992 JRSM, p 195) no longer appear to consider, that the presence of a precipitating infection should be necessary for the' selection of patients involved in the study of chronic fatigue syndromes. The reference they quote', which refers to guidelines laid down at Oxford in 1990, states very clearly that post-infectious patidnts with chirioic fatigue do indeed form a distinct subgroup, and that to fulfil research criteria there, =A be,'defiite evidence of infection at- onset or-r tation'. Having failed to make agch a disn-cti4ioit it is kot, altogether surprising that they go on to concludethat the higher levels of depression foWd -in4Aheir study .... serve to reinforce the -now widely--cuxrent, notion that such patients may be suffering from a depresive illness, of which physical fatiguesisi a. somatic manifestation'. Yet, in a preceding,-editorial (April 1992- JRSM,p 189), Wessely considers some of the evnergiag evidence linking neurological 4d, h,ypothalamicpituitary-axis abnormalities in -patignts who fulfil the post-infection criteria and concludes that ¶Previus views that CFS (chronic fatigue .yndrome -is spmply a form of somatized depression arp no-longer tenable', Conflicting views a) tt,he aeti,plogy and ps±hp; genesis of this syndrOpe e bound to continue, but it now appears that ant even thepsychiatriats can agree. C SHEPHERD

Medical Advisor ---ME AsoCiation Friars Cottage S.u'ery Q eena Square, Chalford Hill, Glos GL6 8EH

References, 1 Sharpe. MC, Archard LC, Banatvala JE, et aL Chronic fatigue syndrome: guidelines for research. J R Soc Med

1991;M4;I18-21 The author replies below: There is now little doubt the prevalence of mood disorder in subjects fulfilling criteria for thb chronic fatigue syndrome (CFS} is increased, and that this increase is net solely a reactioh'-to disability or physical illhess. It is equally clear that not ali subject withGCPS have mood disoider. In 1988 we cbneluded that p6st viral fatigue syndrome was a hete-rogenous conditio, (David et at l1988). The following year- we observed that 'depression is- a sufficient, but not nekiestary; explanation' for CFS(Wessely & Powell,r 1989)t The 1992 paper by Wbod et- al. and my accompanying editorial,- ai'e thus in harmony; and confirm our previous f 'idings I see no point in fuirther arguments as to whtier or not CFS patients'hae; increased rates of- depre§sion (they do), or alternatively that CFS isate same as depression (it isn't). Instead we now tneed t join forces t dicover what lies behind these observatfios. I concluded my editorial by stating that 'd)etors have always disagreed about chronic fatigue, and show few sltns of ceasin& to do so'. I had nft e ed to be proved correct quite so quickly. -S WESSELY Departmeht of Pychological Medicine, King's CelWge Hopital Denmark Hill,,Lqndor SE6 9IS References 1 David A, Wessely S, Pelosi A. Post-viral fatigue: -time for a new approach. BMJ 1988:296:696-9 2 Wessely S, Powell R. Fatigue syndromes: a comparison of chr9nic "postviral" fatigue with neuromuscular and affective disorders. J Neurol Neurosurg Psychiatry!

1989;42:940-8

Modernmedical writing I e,nqoyedreading the opemng comment ofthe article, by Jacks6n, (March 1992 JRSM, p 173) on' thestandardized fashion of modern medical writing as 4iictaed by tfie mandarins of the International to'm,mittee ofMedical Journal Editors. Not only 'all humanity is di&ained out' of the papers, but reading ffiim becomes a very dull ch&e. In my opinion the use of supe'la intMerals .to idlentifyreferences, in th ee,t, ins,ta&fthe name of the firstauthor i similarly m nnoying. is language strument of aj'aEspi,iatixg.i kn&ish tedious? D PECORARI

ading can be u why make At Clinica ootetirq e. ginecologica

Policlinico Borgo Roma -1134Viro~ia, Italy ;

Chronic fatigue syndrome and heterogeneity.

588 Journal of the Royal Society of Medicine Volume 85 September 1992 Chronic fatigue syndrome and heterogeneity One thing which hampers medical res...
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