Evaluation of the relationship between depression and fibromyalgia syndrome: why aren't all patients depressed?

To examine the relationship between fibromyalgia syndrome (FM) and depression by determining the set of factors that differentiate FM patients with and without depressive disorders.

A sample of 69 patients with FM underwent a standardized tender point examination and a semistructured psychological interview and completed a set of self-report inventories.

Of the sample, 39 met criteria for depressive disorder and 30 did not. Depressed patients with FM were significantly more likely to live alone, report elevated functional limitations, and display maladaptive thoughts than nondepressed patients. Nondepressed patients were significantly more likely to have received prior physical therapy than depressed patients. Pain severity, numbers of positive tender points, and pain intensity of tender points and control points did not differentiate the depressed and nondepressed patients. Discriminant analysis revealed that living status, the perception of functional limitations, maladaptive thoughts, and physical therapy treatment together identified diagnoses of depressive disorders for 78% of the patients.

Concurrent depressive disorders are prevalent in FM and may be independent of the cardinal features of FM, namely, pain severity and hypersensitivity to pressure pain, but are related to the cognitive appraisals of the effects of symptoms on daily life and functional activities.