Detecting depression in chronic pain patients: adequacy of self-reports

Depression, a complex psychobiological syndrome, has been found to be prevalent among individuals with chronic pain problems. It has been repeatedly recommended that chronic pain patients be routinely screened for depression. Many self-report questionnaires have been used to screen for depression although few have addressed potential limitations of using a self-report questionnaire to identify depressed chronic pain patients. Among the most serious problems is an over-diagnosis since typical neurovegetative symptoms of depression often resemble patients' medical/physical conditions. Some have suggested that the physical items should be replaced and others have suggested that a higher cut-off criteria for diagnosing depression should be used. In this study, the validity of the Center for Epidemiological Studies-Depression (CES-D) scale was examined to determine (a) its sensitivity, specificity, and positive, and negative predictive value with chronic pain patients, (b) the biasing effect of somatic items, and (c) the optimal cut-off score for diagnosing depression. The results support the predictive validity of the CES-D and suggest that a cut-off score of 19 should be used for diagnosing depression in chronic pain patients rather than the standard cut-off point of 16. Interestingly, the removal of the somatic items did not enhance the effectiveness of the CES-D. The discriminatory ability of somatic items with the total assessment of depression is discussed.