Abnormal pain modulation in patients with spatially distributed chronic pain: fibromyalgia.

Many chronic pain syndromes are associated with hypersensitivity to painful stimuli and with reduced endogenous pain inhibition. These findings suggest that modulation of pain-related information may be linked to the onset or maintenance of chronic pain. The combination of heightened pain sensitivity and reduced pain inhibition seems to predispose individuals to greater risk for increased acute clinical pain. It is unknown whether such pain processing abnormalities may also place individuals at increased risk for chronic pain. Psychophysical methods can be used for the evaluation of pain sensitivity and pain inhibition. Long-term prospective studies that could yield insight into the role of heightened pain sensitivity and pain disinhibition for the development of chronic pain disorders like fibromyalgia in the general population are lacking, however.