This study was conducted to analyze various objective measures of treatment outcome among patients that participated in a multidisciplinary chronic pain treatment program and to compare these measures to the absence or presence of antidepressant medication, the level of depression, and the quality of pain and depression reported. In addition, this study examined whether there are certain patient characteristics that are related to treatment outcome measures. Data was collected from the medical records of 232 patients who were admitted to and treated for various chronic pain syndromes at the Lewis-Gale Hospital Pain Center in Salem, Virginia. Results of the study indicate that when chronic pain patients are subdivided into groups based on antidepressant drug use, depression level, reported quality of pain, and depressive symptomatology, there are distinct and significant differences before treatment when between-group comparisons are made. Within-group comparisons revealed significant differences between pre and post test measures for most groups studied, however, those with the most significant changes in scores included those patients on antidepressant medication, those patients with greater cognitive symptoms of depression, and those patients who were non-depressed. Patient characteristics that were significantly related to outcome included age, gender, duration of pain, employment, workers compensation, and litigation status. / Ph. D.