Clinical aspects of depression in chronic pain patients.

It has been widely recognized that an appreciable proportion of chronic pain patients have depressive disorders. Although numerous studies and several literature reviews have examined the relationship between chronic pain and depression, disorders of mood come in many forms, and little attention has been paid to the different types of depressive disorders found among patients with chronic pain. In this article, the different ways in which a chronic pain patient may manifest depression are discussed. Diagnostic criteria for major depression, dysthymia, and atypical depression are described, and the relevance of these disorders and of masked depression to chronic pain is discussed. The medical illnesses and medications that can cause symptoms of depressive disorders are also briefly described. Depressive disorders and their concomitants are an integral part of the experience of chronic pain and are important in developing an optimal treatment plan. For these reasons, they should be carefully evaluated in all patients with chronic pain.