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Chronic Fatigue Syndrome

  1. Urs M. Nater1,
  2. Andrew H. Miller2,
  3. William C. Reeves3,
  4. Charles Raison4

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0176

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Nater, U. M., Miller, A. H., Reeves, W. C. and Raison, C. 2010. Chronic Fatigue Syndrome. Corsini Encyclopedia of Psychology. 1–3.

Author Information

  1. 1

    University of Zurich, Switzerland

  2. 2

    Emory University School of Medicine

  3. 3

    Centers for Disease Control and Prevention, Atlanta, GA

  4. 4

    Emory University School of Medicine

Publication History

  1. Published Online: 30 JAN 2010


Although diseases similar to chronic fatigue syndrome (CFS) have been recognized for centuries under various rubrics, strict diagnostic criteria for conditions dominated by medically unexplained chronic fatigue were first proposed in 1988. Current diagnostic criteria were originally crafted in 1994 by an International Chronic Fatigue Syndrome Study Group as an attempt to standardize patient populations included in research studies. The International CFS Research Case Definition requires chronic fatigue of at least six-months duration; this fatigue cannot be substantially alleviated by rest, is not the result of ongoing exertion, and is associated with substantial reductions in occupational, social, and personal activities. In addition, at least four out of the following eight symptoms must occur with fatigue in a six-month period: prolonged extraordinary postexertional fatigue, impaired memory or concentration, unrefreshing sleep, aching or stiff muscles, multijoint pain, sore throat, tender glands, and new headaches (Fukuda et al., 1994). Importantly, the research case definition precludes classification as CFS if a patient has an identifiable medical cause of being fatigued. Similarly, individuals with certain psychiatric conditions cannot be classified as CFS in research studies. Exclusionary psychiatric conditions include schizophrenia, bipolar disorder, and melancholic major depression. Notably, comorbidity with psychiatric disorders is relatively high. Recent data indicate that almost 60% of CFS cases in the population suffer from at least one comorbid psychiatric condition, with affective disorders being the most prevalent ones.


  • chronic fatigue syndrome;
  • functional symptoms;
  • immune system;
  • hormones;
  • autonomic nervous system;
  • stress