Prognosis of depression in the elderly in comparison with adult age. Is there a significant clinical difference?

Abstract

Major depressive disorder is typically a chronic disorder in which the chances of suffering a single non-recurring episode are low. To date it has been uncertain how age moderates prognosis. It has been especially difficult to separate the effect of age of first episode onset from the overall effect of age at the time of recruitment. From a methodological perspective, this question is best studied in inception cohort studies rather than naturalistic studies. In inception cohort studies, all patients receive treatment under controlled conditions and therefore the effect of age (if any) may be more apparent. In addition, the best evidence comes from comparative studies which have examined older and middle aged patients within the same study.

After conducting a thorough review of the literature, we have found three comparative inception cohort studies of episode remission in older versus middle aged patients. We found only one comparative inception cohort study of relapse and recurrence in older versus middle aged patients. This evidence suggests that depression in the elderly (those of older chronological age) responds equally to the initial treatment but has a more adverse longitudinal trajectory than depression in middle age. An early age of illness onset also seems to adversely affect prognosis in comparison to those with a first onset in later life who do not have medical comorbidity. The effect of age on prognosis may be largely explained by factors