Depression and somatization in the chronic fatigue syndrome

To report the prevalence, clinical features, and diagnostic associations of the proposed chronic fatigue syndrome (CFS) in a cohort of patients with chronic fatigue and to assess the usefulness of a structured psychiatric interview for detecting previously unrecognized psychiatric morbidity in patients with CFS.

A consecutive sample of 200 adult patients with a chief complaint of chronic fatigue was prospectively evaluated in a referral-based clinic within a university general medicine practice. All patients received a thorough medical history, physical examination, diagnostic laboratory testing, and portions of the Diagnostic Interview Schedule, version III-A. The criteria for CFS were applied, and patients with CFS were compared with matched control subjects from the inception cohort.

The 60 patients with CFS had similar likelihoods of current psychiatric disorders (78% versus 82%), active mood disorders (73% versus 77%), and preexisting psychiatric disorders (42% versus 43%) when compared with fatigued control subjects. Patients with CFS were more likely to have somatization disorder (p less than 0.001) and to attribute their illness to a physical cause (p less than 0.005) than fatigued controls. Patients with CFS also displayed functional symptoms, often lifelong, which are not part of the case definition of CFS. Depressive features in patients with CFS were similar to those of control subjects, but a trend toward suicidal behavior was noted.

Patients with CFS have a high prevalence of unrecognized, current psychiatric disorders, which often predate their fatigue syndrome. Assessment of patients with CFS should include a structured psychiatric evaluation.