Cognitive predictors of depression in chronic low back pain: toward an inclusive model.

Previous research has linked cognitive distortion, perceived interference with instrumental activities, and self-control to depression in chronic pain patients, though to date no study has examined all three variables concurrently. The present study investigated these three cognitive mediators in a comprehensive model to determine whether each variable represented an independent dimension in the pain-depression relationship. Results in a sample of 74 chronic low back pain patients revealed that a regression model containing all three cognitive variables had the strongest association with depressive symptoms. Consistent with a cognitive mediational model of the pain-depression relation, when self-control, cognitive distortion, and interference were held constant, pain and disability did not have a significant association with self-reported depression. These findings indicate that a comprehensive cognitive model of depression and chronic pain will need to incorporate all three cognitive variables.