Chronic fatigue syndrome.

Fatigue is a very common complaint but it is typically transient, self-limiting, or explained by other circumstances. Chronic fatigue syndrome (CFS) is characterized by persistent or relapsing unexplained fatigue of new or definite onset lasting for at least 6 months. It is not a new condition and corresponds very clearly to an illness called neurasthenia, commonly seen in Europe around the turn of the twentieth century. The terms 'myalgic encephalomyelitis' (ME) and 'postviral fatigue syndrome' have also been used to describe CFS but are misleading and unsatisfactory: ME implies the occurrence of a distinct pathological process whereas postviral fatigue syndrome wrongly suggests that all cases are preceded by a viral illness. Operational criteria developed for research purposes by the U.S. Centers for Disease Control and Prevention (CDC) (Fukuda et al., 1994) and by researchers in Oxford, United Kingdom (Sharpe et al., 1991), are now widely used to define CFS. The CDC criteria require at least 6 months of persistent fatigue causing substantial functional impairment and at least four somatic symptoms (from a list of eight) occurring with the fatigue in a 6-month period. The presence of medical disorders that explain prolonged fatigue excludes a patient from a diagnosis of CFS, as do a number of psychiatric diagnoses. Although the British definition is similar, it differs by requiring both physical and mental fatigue but no physical symptoms. By including a requirement for several physical symptoms, the CDC definition reflects the belief that an infective or immune process may underlie the syndrome. A systematic review of studies describing the prognosis of CFS identified 14 studies that used operational criteria to define cohorts of patients with CFS (Cairns & Hotopf, 2005). The review looked at the course of CFS without systematic intervention but, as we have seen, there is now increasing evidence for the effectiveness of CBT and graded exercise therapy (GET). More recent evidence suggests that recovery from CFS is possible and that CBT and GET are the therapies most likely to lead to recovery (White et al., 2013). (PsycINFO Database Record (c) 2019 APA, all rights reserved)