Background and Objectives Reflex sympathetic dystrophy (RSD) has sometimes been hypothesized to derive from a unique psychological predisposition because of its enigmatic features, as well as the profound behavioral and emotional characteristics manifested by some patients. This study compares the psychological characteristics of RSD and myofascial pain syndrome (MPS) patients to discern the extent of any aspects unique to RSD.

Methods The patients included 58 with RSD and 214 with MPS, all of whom completed the Minnesota Multiphasic Personality Inventory (MMPI) as well as a pain questionnaire. Additional pertinent demographic and clinical characteristics were ascertained.

Results The only significant demographic group differences revealed a higher proportion of RSD patients not working (P < .05) and a higher proportion of RSD patients receiving Workers' Compensation payments (P < .001). The RSD patients had shorter duration of pain (P < .01) and were taking fewer pain medications (P < .01) than the MPS group, but the two groups had comparable numbers of pain-related surgeries, pain intensity ratings, perceived ability to cope, and ongoing extent of involvement in social or recreational activities. A wide range of functioning was in evidence for both groups on the MMPI clinical scales, but with duration as a covariate, the RSD group had significantly (P < .05) lower scores on the hypochondriasis, depression, hysteria, and psychasthenia scales and higher scores on the hypomania scale. The duration covariate was significant (P < .05) only for the infrequency (rare responses) and depression scales. Duration and certain scale scores were inversely correlated.

Conclusions With only a few exceptions, RSD and MPS patients appear comparable with respect to a wide range of demographic, clinical, and psychological functioning indices. A specific psychological profile, uniquely neurotic or otherwise, has yet to be demonstrated in terms of any etiologic or maintenance factors in RSD.