The epidemiology of fatigue: more questions than answers.

Accepted for publication February 1991 Fatigue syndromes, though recognised for some time, have recently attracted a variety of new diagnostic labels, as well as both professional and media controversy. However, most of the arguments surround the interpretation of small hospital based case-control studies using highly selected groups of patients.1 There is relative silence on population based studies, which perhaps contributes to the lack of concensus. This paper reviews the epidemiology of fatigue in the general population and in primary care and examines potential sources of bias in hospital based studies.