BACKGROUND This study examines whether cognitive dysfunction in chronic fatigue may be accounted for by depression and anxiety or is due to brain pathology evident on magnetic resonance imaging (MRI).
METHOD Twenty-six subjects with chronic fatigue, with and without coexisting depression, and 18 age-matched normal controls were recruited from primary care following a presumed viral illness six months previously. Comparison was made with 13 psychiatric controls with depressive illness on standardised cognitive tests. MRI determined the presence of cerebral white-matter lesions.
RESULTS No substantial differences in performance were shown between subjects with chronic fatigue, most of whom met the criteria for chronic fatigue syndrome, and controls. Subjective cognitive dysfunction increased with psychopathology. White-matter lesions were found in a minority from all groups. Improvement in fatigue and depression coincided with improved performance on cognitive measures.
CONCLUSIONS Subjective complaints of cognitive impairment are a prominent feature of chronic fatigue, but objective cognitive and MRI abnormalities are not. Such complaints probably reflect psychopathology rather than a post-viral process.