A comparison of pain perceptions in women with fibromyalgia and rheumatoid arthritis: relationship to depression and pain extent.

Two studies were conducted to characterize the pain of fibromyalgia syndrome (FMS); to compare it to rheumatoid arthritis (RA) pain; and to examine the relationships between depression, pain extent, and pain description. Two methods of administering the McGill Pain Questionnaire (MPQ) were used. When the MPQ was administered in the standard manner, FMS pain could not be distinguished from RA pain. When participants were allowed to select as many words from an adapted MPQ as they wished, significant differences in word choice emerged. Depression and pain extent were major predictors of group differences in the evaluation of pain. However, depression scores contributed only 50% of the explanation for the differences in pain extent, with group membership contributing the other 50%. These findings suggest that the character and extent of pain in FMS are at least partially due to peripheral sensory components and not simply centrally controlled pain amplification secondary to depression.