Discriminating between chronic fatigue syndrome and depression: a cognitive analysis

Background. Chronic fatigue syndrome (CFS) and depression share a number of common symptoms and the majority of CFS patients meet lifetime criteria fo r depression. While cognitive factors seem key to the maintenance of CFS an d depression, little is known about how the cognitive characteristics diffe r in the two conditions. Methods. Fifty-three CFS patients were compared with 20 depressed patients and 38 healthy controls on perceptions of their health, illness attribution s, self-esteem, cognitive distortions of general and somatic events, sympto ms of distress and coping. A 6 month follow-up was also conducted to determ ine the stability of these factors and to investigate whether CFS-related c ognitions predict ongoing disability and fatigue in this disorder. Results. Between-group analyses confirmed that the depressed group was dist inguished by low self-esteem, the propensity to make cognitive distortions across ah situations, and to attribute their illness to psychological facto rs. In contrast, the CFS patients were characterized by low ratings of thei r current health status, a strong illness identity, external attributions f or their illness, and distortions in thinking that were specific to somatic experiences. They were also more likely than depressed patients to cope wi th their illness by limiting stress and activity levels. These CFS-related cognitions and behaviours were associated with disability and fatigue 6 mon ths later. Conclusions. CFS and depression can be distinguished by unique cognitive st yles characteristic of each condition. The documented cognitive profile of the CFS patients provides support for the current cognitive behavioural mod els of the illness.