The relationship between fibromyalgia and major depressive disorder

Is fibromyalgia associated with major depressive disorder? If so, what is the nature of this association? In an attempt to address these questions, the authors review studies of patients with fibromyalgia, examining phenomenology, personal and family history of psychiatric and medical disorders, response to antidepressant medications, and results of laboratory tests. Although this evidence is not entirely consistent, the great majority of studies favor an association between fibromyalgia and major depressive disorder. These findings cannot be explained by the hypothesis that fibromyalgia causes depression or vice versa. Therefore, it appears most likely that both disorders share some unknown common etiologic factor.