Cluster analyses of pain patients' responses to the SCL-90R.

This study sought to identify distinct subgroups of chronic pain patients based on responses to the Symptom Checklist 90-revised (SCL-90R), a measure of psychological distress. Two scoring methods were used: the standard scoring that accompanies the manual, and a scoring method based upon factor scores obtained in an earlier study using low back pain patients. Two separate cluster analyses assigned patients into 2 groups: one based on standard scores and one based on factor scores. Results of this study support the hypothesis that distinct and replicable subgroups of chronic pain patients can be identified using the SCL-90R. Depending upon group membership, patients significantly differed on measures of qualitative pain and quantitative pain report, depressive symptoms, medication usage, and pain-related behaviors. This study supports the use of SCL-90R factor scoring with pain patients as greater differentiation between clusters was found for pain report and pain-related behavior when this method was used. Guidelines for clinical application of SCL-90R cluster groups is provided.