Chronic pain and depression. I. Classification of depression in chronic low back pain patients.

An association between chronic pain and depression has been recognized for a long time. However, the exact nature of this relationship remains unclear. The authors studied 71 patients for affective disorders and schizophrenia-lifetime version (SADS-L). Based on the interviews, we were able to identify 31 patients with major depression, 8 patients with minor depression and 18 with intermittent depressive disorder as defined by Research Diagnostic Criteria. Item analysis using the Hamilton Depression Rating Scale and the Montgomery-Asberg Depression Rating Scale showed that the items did not discriminate in patients with major depression the presence of organic findings. However, most of the items significantly discriminated between the various types of depression and patients without depression. The occurrence of clearly defined depression points to several avenues of research aimed at clarifying the incidence etiology and treatment of depression in these patients.