12 Vascular risk factors for depression and apathy Late-life depression Depression is one of the most common and disabling psychiatric disorders in later life. Box 1 presents the diagnostic criteria for a major depression. The prevalence of major late-life depression ranges between 0.9-9.4% for those living in private households and between 14-42% for those living in institutions 1, where it needs to be noted that subthreshold depression (i.e. when older adults suffer from depressive symptoms without meeting the full criteria for a major depression) is even more prevalent 2. The risk of becoming depressed in later life is raised in women and in individuals with a somatic illness, cognitive or functional impairment, lack or loss of social contacts and/or a history of depression 1. In fact, besides the risks that are particularly common in late life (e.g. somatic disease and functional and cognitive impairment), all risk factors for depression across a person’s lifespan can play a role in the development of late-life depression, also risk factors such as genetic predisposition, early life trauma and social stress that are typically associated with early-onset depression 3. In elderly persons coping with depression, particularly in those suffering from severe depression, chronic disease and loneliness, the risk of chronicity is higher than it is in younger depressed individuals 4. Antidepressant treatments, electroconvulsive therapy (ECT) and psychotherapy can be effective in older people 5, but often late-life depression goes unrecognized and untreated 6. In thosewho do receive treatment for their depression, older age, more severe and longer duration of the depression, comorbid anxiety, physical illness and executive dysfunction predict a worse outcome 7. The consequences of major and subthreshold depression in late life are severe: depressed elderly persons not only suffer from the depression itself, they also use more health care, particularly other types of health care than mental health care, and experience higher levels of functional and cognitive impairment and a lower quality of life, while their caregivers experience a high burden 8. Also, the risk of mortality is elevated in late-life depression 9, part of which is explained by a raised cardiovascular 10 11 and cerebrovascular mortality 12.