Chronic fatigue syndrome: it's tiring not knowing much—an in-depth review for occupational health professionals

Abstract

Fatigue is an incredibly common symptom in medical settings. In the Office of National Statistics Survey 2000 (1), a degree of limiting fatigue was reported by 27% of working-age adults. Although it is claimed that about three-quarters of these patients in primary care go on to develop chronic symptoms, this is at odds with the reported point prevalence of only up to 3%. The vast majority of this fatigue falls within the 'medically unexplained' (2) category yet does not meet the diagnostic criteria for chronic fatigue syndrome (CFS). Even those that might do are often not diagnosed as such by physicans (3). As Ranjith ((4), this issue) demon- strates, there are several sets of different diagnostic criteria that make this difficult area even more complex. A primary agreement seems to be the requirement for the fatigue to have lasted for 6 months or more and to be associated with a substantial degree of impairment. It is this impairment that is the primary reason for occu- pational health involvement. Further symptoms must co- occur with the fatigue over the 6 month period (impaired memory or concentration, sore throat, tender glands, aching or stiff muscles, post-exertional fatigue, multi-joint pain, unrefreshing sleep and new headaches), although the actual number required fluctuates. Other clinically important physical causes preclude diagnosis, as do underlying serious psychiatric conditions such as schizophrenia. The common co-morbidity with anxiety and depression does not rule out the diagnosis and has complicated research, treatment and policy. A lot of published work covers either less severe conditions or those with shorter duration. These con- ditions receive labels such as 'chronic-fatigue like syndrome' or 'idiopathic chronic fatigue'. A recent review covered work in Holland amongst this group of subjects