Prognosis of Depression in Old Age Compared to Middle Age: A Systematic Review of Comparative Studies

Abstract

Depression in old age has a poor long-term prognosis; equal evidence shows that the same is true of depression in middle age. The authors sought to identify research that has compared the prognosis of depression in late life with depression in midlife under similar conditions. The authors separated studies that examined age at presentation/recruitment from studies of age at first episode of depression, studies that examined remission/response from those that examined relapse/recurrence, and those that examined mortality/risk of dementia. Evidence suggests that response and remission rates to pharmacotherapy and ECT are not sufficiently different in old-age depression and middle-age depression to be clinically significant. Older patients at study entry appear to have a higher risk of further episodes, which informs the debate about the duration of continuation treatment for depression in older people. However, older patients and patients with late-onset depression are at increased risk of medical comorbidity. Medical comorbidity is a risk factor for inferior treatment response and poor antidepressant tolerability. Elderly patients with early-onset depression are more likely to have had a higher number of previous episodes, which also adversely influences prognosis compared to elderly depressed patients with late onset of illness. With control for confounding variables, remission rates of depression in patients in late life are little different from those in midlife, but relapse rates appear higher. Findings underline the importance of assessing factors related to patient age and not just to age itself in evaluations of risk factors for poor prognosis.