Psychological Medicine



Fatigue and psychiatric disorder: different or the same?


G. VAN DER LINDEN a1c1, T. CHALDER a1, I. HICKIE a1, A. KOSCHERA a1, P. SHAM a1 and S. WESSELY a1
a1 From the Department of Psychiatry, University of Stellenbosch, Tygerberg, South Africa; Department of Psychological Medicine, Institute of Psychiatry and King's College School of Medicine, London; and School of Psychiatry, St George Hospital and Community Health Service, Academic Department of Psychiatry, University of New South Wales, Kogarah, NSW, Australia

Abstract

Background. Fatigue and psychiatric symptoms are common in the community, but their association and outcome are sparsely studied.

Method. 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.


Correspondence:
c1 Address for correspondence: Dr G. van der Linden, Department of Psychiatry, Faculty of Medicine, PO Box 19063, Tygerberg, 7505, South Africa.


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