Chronic back pain and major depression in the general Canadian population :

To determine the current status for the association of chronic pain and depression and to review the evidence for whether depression is an antecedent or consequence of chronic pain (CP). A computer and manual literature review yielded 191 studies that related to the pain-depression association. These reports were reviewed and sorted into seven categories relating to the topic of this paper. Eighty-three studies were then selected according to inclusion criteria and subjected to a structured review. Any medical treatment setting including pain treatment as inclusion criteria for selection of studies. Any patients with any type of chronic pain. The reviewed studies were consistent in indicating that there is a statistical relationship between chronic pain and depression. For the relationship between pain and depression, there was greater support for the consequence and scar hypotheses than the antecedent hypothesis. Depression is more common in chronic pain patients (CPPs) than in healthy controls as a consequence of the presence of CP. At pain onset, predisposition to depression (the scar hypothesis) may increase the likelihood for the development of depression in some CPPS. Because of difficulties in measuring depression in the presence of CP, the reviewed studies should be interpreted with caution.

We describe the relationship of depression and depressive symptoms to disability days and days lost from work in 2980 participants in the Epidemiologic Catchment Area Study in North Carolina after 1 year of follow-up. Compared with asymptomatic individuals, persons with major depression had a 4.78 times greater risk of disability (95% confidence interval, 1.64 to 13.88), and persons with minor depression with mood disturbance, but not major depression, had a 1.55 times greater risk (95% confidence interval, 1.00 to 2.40). Because of its prevalence, individuals with minor depression were associated with 51% more disability days in the community than persons with major depression. This group was also at increased risk of having a concomitant anxiety disorder or developing major depression within 1 year. We conclude that the threshold for identifying clinically significant depression may need to be reevaluated to include persons with fewer symptoms but measurable morbidity. Only by changing our nosology can the societal impact of depression be adequately addressed.