Aging and late-life depression.

OBJECTIVES The objective of this study is to examine the relationship between age and depression among people aged 65 and older. METHOD The study uses three waves of longitudinal data (1991, 1996, 2001) from a community and institutional sample of Canadians aged 65 and older. The study uses generalized linear mixed-model techniques to estimate the trajectories of depressive symptoms and major depression in late life. RESULTS There is a linear increase in depressive symptoms after age 65, but this occurs in the context of medical comorbidity and is not an independent effect of aging. There is a significant u-shaped relationship between age and major depression, after adjusting for selected covariates. DISCUSSION The relationship between age and late-life depression is complex, and it depends on how the dependent variable is measured. Late-life depression develops through a different set of risk factors than it does in earlier stages of the life course. The "fourth age" appears to be a period of psychiatric morbidity.