What are the causes of late-life depression?

Although depression in old age is less common than depression in younger populations, it still affects more than 1 million community-living older adults. Depression in late life has been associated with reduced quality of life and increased mortality from both suicide and illness. Its causes are multifactorial but are prominently related to both biologic and social factors. Psychological factors, although less studied in elders, are also important in understanding its cause. In this article, multiple facets of late-life depression are reviewed, including its clinical presentation, epidemiology, and biopsychosocial causes.