Review of clinical and psychobiological dimensions of the chronic fatigue syndrome: differentiation from depression and contribution of sleep dysfunctions

Chronic fatigue syndrome (CFS) is a disabling condition characterized by subjective fatigue, mental and physical fatigability, a whole range of somatic symptoms and a poor quality of sleep. Its physiopathology is largely unknown. Several clinical and biological differences were observed between CFS and major depression. A classical conceptualization of masked (or somatized expression of ) depression is therefore no longer tenable. Sleep anomalies were reported in all studies published to date. However, these sleep anomalies do not seem to explain a major part of the symptomatology of CFS. The contribution of sleep abnormalities to the development and chronicity of CFS should be further studied. CFS can be considered as a somatoform condition. CFS is like most functional disorders a clinically and biologically heterogeneous condition. The best available treatment to date is cognitive-behavioural therapy.