Self-efficacy and pain behavior among subjects with fibromyalgia.

Given the lack of objective physical measures for assessing fibromyalgia syndrome (FS), the role of pain assessment is particularly important. The role of psychological factors is controversial among FS patients. This study was designed to better understand the relationship between pain behaviors and psychological variables. Specifically, this study (1) refined a pain behavior observation (PBO) methodology for use with FS patients, (2) determined whether stretching is a valid pain behavior, and (3) assessed whether psychological variables including self-efficacy and/or depression can predict pain behaviors after controlling for disease severity and age. The 73 FS subjects meeting the American College of Rheumatology classification system completed questionnaires measuring self-efficacy, depression, and pain. Trained physicians conducted tender-point examinations. Subjects were video-taped using a standardized procedure. Two trained raters independently coded all pain behaviors. Kappa coefficients and correlations among pain behaviors and self-reported pain indicated that the PBO method was both reliable and valid. However, the newly defined pain behavior 'stretching' was found to be negatively associated with self-reported pain. Hierarchical multiple regression (MR) analyses revealed that depression did not predict pain behavior over and above myalgic scores and age; however, in 3 separate MR analyses, self-efficacy for function, pain, and other symptoms each predicted pain behavior over and above myalgic scores and age. This study indicated that the original pain behavior scoring methodology is appropriate for use with the FS population and should not be modified to include the pain behavior 'stretching'. Self-efficacy was related to pain behavior while depression was not among this FS sample.