The good news for older adults is that, contrary to common belief, depression is not a normal or inevitable outcome of aging. But the ageist expectation that it is frequently results in failure to take steps to overcome it. “There’s nothing to be done. They’re just old.” This attitude too often robs older people of opportunities to enjoy life.
In fact, each year major depressive disorder affects fewer than 5 percent of adults 65 or older who live in the community. The rate is higher among older adults with serious chronic health conditions, those who need home health care and those who are institutionalized.
A much higher proportion of older adults who live in the community — perhaps 20 percent — experience symptoms and forms of mood disorders, such as dysthymia or sub-syndromal depression, that are not as severe as major depressive disorder but may have nearly as much negative impact.
via Michael Friedman, L.M.S.W.: Elderly Depression: Is Melancholy an Inevitable Outcome of Getting Old?.