Fibromyalgia and psychopathology: is fibromyalgia a form of "affective spectrum disorder"?

Several lines of evidence support a relationship between fibromyalgia and various forms of psychopathology, particularly major affective (mood) disorder. We evaluate 3 hypotheses that might explain this relationship: (1) that psychopathology is an effect of fibromyalgia; (2) that fibromyalgia is an effect of psychopathology; or (3) that both fibromyalgia and its associated psychopathology are caused by a common (but as yet unknown) abnormality. The third hypothesis may be expanded to the more general proposition that fibromyalgia, major affective disorder, and several other medical and psychiatric disorders may represent a family of related conditions--provisionally named "affective spectrum disorder" (ASD)--that share common pathophysiologic features.