title: A population-based incidence study of chronic fatigue.
abstract: BACKGROUND
  Most research on syndromes of chronic fatigue has been conducted in clinical settings and is therefore subject to selection biases. We report a population-based incidence study of chronic fatigue (CF) and chronic fatigue syndrome (CFS).
  
  
  METHODS
  Questionnaires assessing fatigue and emotional morbidity were sent to 695 adult men and women who had replied to a postal questionnaire survey 1 year earlier. Possible CFS cases, subjects with probable psychiatric disorder and normal controls were interviewed.
  
  
  RESULTS
  Baseline fatigue score, the level of emotional morbidity and a physical attribution for fatigue were risk factors for developing CF. However, after adjusting for confounding, premorbid fatigue score was the only significant predictor. A minority of CF subjects, all female, had consulted their general practitioner; higher levels of both fatigue and emotional morbidity were associated with consultation. Possible CFS cases reported similar rates of current and past psychiatric disorder to psychiatric controls, but after controlling for fatigue or a diagnosis of neurasthenia the current rates were more similar to those of normal controls. Two new cases of CFS were confirmed.
  
  
  CONCLUSIONS
  Both fatigue and emotional morbidity are integral components of chronic fatigue syndromes. The demographic and psychiatric associations of CFS in clinical studies are at least partly determined by selection biases. Given that triggering and perpetuating factors may differ in CFS, studies that examine the similarities and differences between chronic fatigue syndromes and psychiatric disorder should consider both the stage of the illness and the research setting.
authors.affiliation: Edinburgh University Department of Psychiatry, Royal Edinburgh Hospital.
authors.forename: S M
authors.initials: SM
authors.lastname: Lawrie
authors.forename: D N
authors.initials: DN
authors.lastname: Manders
authors.forename: J R
authors.initials: JR
authors.lastname: Geddes
authors.forename: A J
authors.initials: AJ
authors.lastname: Pelosi
mesh_terms: D000328:Adult; D000342:Affective Symptoms / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003430:Cross-Sectional Studies; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010552:Personality Assessment; D011159:Population Surveillance; D012494:Sampling Studies; D012606:Scotland / Q000453:epidemiology; D013001:Somatoform Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology