Predicting treatment response in depressed and non-depressed chronic pain patients.

Although it has often been observed that chronic pain and depression are associated, there have been few systematic comparisons of chronic pain patients with and without depression. In the study reported in this article, depressed and non-depressed chronic pain patients were found to be quite similar with respect to demographic, pain-related, and treatment response variables. The primary aim of the study, however, was to examine the hypothesis that treatment response in these two groups of patients would be predicted by different patterns of variables. In non-depressed patients, beneficial response to treatment was related to a greater number of treatment visits, not receiving workmen's compensation, fewer previous types of treatment, and low back pain. As predicted, a different pattern of predictors of treatment response was found for the depressed patients, who were more likely to benefit when they were employed at the beginning of treatment and when their pain was of shorter duration. These results suggest that activity and active involvement in treatment are particularly important with chronic pain patients who are depressed. In addition, they suggest that the best prediction of treatment response in future research on chronic pain patients may be achieved by dividing patients into groups based on psychological characteristics.