Background: The association between depression and pain, function, medically unexplained symptoms and psychophysiological syndromes such as irritable bowel syndrome has not been explored before in chronic fatigue syndrome.
Methods: Cross-sectional controlled study of the current prevalence of psychophysiological syndromes, pain, function and lifetime prevalence of medically unexplained symptoms in 77 out-patients with chronic fatigue syndrome (CFS) without DSM-III-R depression, 42 CFS out-patients with DSM-III-R depression and 26 out-patient with primary DSM-III-R depression.
Results: Both CFS groups differed significantly from the primary depression group but not each other in the prevalence of tension headaches (P < 0.001), reporting of widespread bodily pain (P < 0.001) and the number of lifetime medically unexplained symptoms (P < 0.001). The three groups did not significantly differ in the prevalence of irritable bowel syndrome or fibromyalgia. CFS patients with depression were more impaired in social function than other CFS patients.
Conclusion: Depression is not associated with the reporting of pain, psychophysiological syndromes and medically unexplained symptoms in CFS patients. Depression is associated with decreased social function in CFS patients.
Limitations: Study depended on recall of symptoms, not confirmed by medical records and current investigations. Patients with depression were taking antidepressants.
Clinical relevance: Treating depression in chronic fatigue syndrome is unlikely to diminish reporting of pain and medically unexplained symptoms but may improve social function.