title: Fatigue and psychiatric disorder: different or the same?
abstract: BACKGROUND
  Fatigue and psychiatric symptoms are common in the community, but their association and outcome are sparsely studied.
  
  
  METHODS
  A total of 1177 patients were recruited from UK primary care on attending their general practitioner. Fatigue and psychiatric disorder was measured at three time points with the 12-item General Health Questionnaire and the 11-item Fatigue Questionnaire.
  
  
  RESULTS
  Total scores for fatigue and psychiatric disorder did not differ between the three time points and were closely correlated (r around 0.6). The association between non-co-morbid ('pure') fatigue and developing psychiatric disorder 6 months later was the same as that for being well and subsequent psychiatric disorder. Similarly, having non-co-morbid psychiatric disorder did not predict having fatigue any more than being well 6 months previously. Between 13 and 15% suffered from non-co-morbid fatigue at each time point and 2.5% suffered from fatigue at two time points 6 months apart. Less than 1% of patients suffered from non-co-morbid fatigue at all three time points.
  
  
  CONCLUSIONS
  The data are consistent with the existence of 'pure' independent fatigue state. However, this state is unstable and the majority (about three-quarters) of patients become well or a case of psychiatric disorder over 6 months. A persistent, independent fatigue state lasting for 6 months can be identified in the primary-care setting, but it is uncommon of the order of 2.5%. Non-co-morbid (pure) fatigue did not predict subsequent psychiatric disorder.
authors.affiliation: Department of Psychiatry, University of Stellenbosch, Tygerberg, South Africa.
authors.forename: G
authors.initials: G
authors.lastname: van der Linden
authors.forename: T
authors.initials: T
authors.lastname: Chalder
authors.forename: I
authors.initials: I
authors.lastname: Hickie
authors.forename: A
authors.initials: A
authors.lastname: Koschera
authors.forename: P
authors.initials: P
authors.lastname: Sham
authors.forename: S
authors.initials: S
authors.lastname: Wessely
mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D003866:Depressive Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D004739:England; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care