THE NATURE OF FATIGUE IN MULTIPLE-SCLEROSIS

The aim of this cross-sectional descriptive study was to determine whe ther people with multiple sclerosis differentially experience physical and mental fatigue, and whether the pattern of fatigue is influenced by mood, disease duration, or disease course. Seventy-eight consecutiv e out-patients with multiple sclerosis were asked to complete the Fati gue Rating Scale (FRS) and the Hospital Anxiety and Depression Scale ( HAD). Sixty-eight (87%) subjects completed the questionnaires. Fifty-e ight (85%) subjects in this group scored above the recommended cut-off for fatigue on the FRS scale. Both the mental fatigue score and the t otal fatigue score were positively correlated with the depresssion and anxiety scores on the HAD scale. There was no significant correlation between the physical fatigue score and either of the HAD subscale sco res. There was no significant association between duration of disease or disease course and the total scores or subscale scores of the FRS a nd HAD. This is the first reported study to differentiate between ment al and physical fatigue in multiple sclerosis and to demonstrate a sig nificant correlation between fatigue and mood level. This has importan t implications for the effective treatment of fatigue in multiple scle rosis. (C) 1998 Elsevier Science Inc.