title: Functional incapacity and physical and psychological symptoms: how they interconnect in chronic fatigue syndrome.
abstract: BACKGROUND
  It has been argued that perceived functional incapacity might be a primary characteristic of chronic fatigue syndrome (CFS) and could be explained by physical symptoms. If so, it could be expected to be closely associated with physical, but not psychological symptoms. The study tests this hypothesis.
  
  
  METHODS
  The sample consisted of 73 patients, with a diagnosis of CFS according to the Oxford criteria, randomly selected from clinics in the Departments of Immunology and Psychiatry at St. Bartholomew's Hospital, London. The degree of fatigue experienced by patients was assessed using the Chalder Fatigue Questionnaire and a visual analogue scale. Self-rated instruments were used to measure physical and social functioning, quality of life, and physical and psychological symptoms.
  
  
  RESULTS
  Principal-component analysis of all scale scores revealed 2 distinct components, explaining 53% of the total variance. One component was characterized by psychological symptoms and generic quality of life indicators, whilst the other component was made up of physical symptoms, social and physical functioning and indicators of fatigue.
  
  
  CONCLUSIONS
  The findings suggest that perceived functional incapacity is a primary characteristic of CFS, which is manifested and/or explained by physical symptoms.
authors.affiliation: Unit for Social and Community Psychiatry, Barts' and the London School of Medicine, Queen Mary University of London, London, UK. s.priebe@qmul.ac.uk
authors.forename: Stefan
authors.initials: S
authors.lastname: Priebe
authors.forename: Walid K H
authors.initials: WK
authors.lastname: Fakhoury
authors.forename: Peter
authors.initials: P
authors.lastname: Henningsen