Depression in chronic low back pain patients: diagnostic efficiency of three self-report questionnaires.

Three self-report questionnaires (the Beck Depression Inventory, the MMPI-D scale, and the depression subscale of the Middlesex Hospital Questionnaire) were examined to see how accurately they could identify chronic low back pain patients who were suffering depression, as defined by DSM-III criteria. According to these criteria, 25% of a sample of 68 patients currently were depressed, a rate comparable to those reported by other studies that have used standardized criteria. On the basis of relative conditional probability ratios, the BDI was shown to be the most efficient instrument for identifying these cases and represents an excellent screening device for depression with this population. The individual items of the BDI then were examined, and the conditional probability ratios revealed that several may be helpful as indicators of possible depression among chronic low back pain patients. The relationship between depression and chronic pain is reconsidered in the light of these results.