ABSTRACT
Affective disorders in late life may begin prior to and then persist into old age or may have their very first onset later in life. In the late mid- to late-1990s the concept evolved of a sub-type of depression in which vascular aetiology is particularly important – 'vascular depression'. Social isolation, lack of social networks and loss of roles have long been recognised as factors important in late-life depression, with evidence that socially less-well-engaged individuals are more likely to be depressed. Family history of affective illness is perhaps twice as common in early-onset than in late-onset depression, indicating a greater genetic aetiological component to early-onset illness. Bipolar affective disorder and unipolar depression are considered separately as their aetiologies may differ. Depression in dementia appears unlikely to be due simply to the psychological impact of suffering a degenerative disorder, as its relationship with specific dementias varies in terms of persistence, suggesting that the underlying pathology may modify the course of depression.
