[Descriptive epidemiology and risk factors of depression in the elderly].

Depressive symptoms are frequent among the elderly, and seriously impair their quality of life. The prevalence of depressive symptoms is difficult to evaluate on account of several epidemiological problems, such as the various definitions of "depression", which often prevent comparisons between studies. The second major difficulty is related to the selection bias due to differences in populations studied, and to the high risk of refusal to participate among the depressed subjects. Nevertheless, the prevalence has been estimated, in general population, from 1 to 4% for major depression according to the DSM-IV criteria, and from 8 to 16% for depressive symptoms which may require treatment. The heterogeneity of the symptomatology of depression in the elderly, with atypical clinical feature, leads to underestimate its diagnosis and lack of proper medical care. However, effective treatments exist and most cases of depression among elderly are treatable. In the literature, many risk factors of depression among the elderly have been identified : female sex, low socio-economical level, bereavement, prior depression, co-morbidities, disability, cognitive deterioration and vascular factors. To decrease the consequences of depression and to improve the quality of life of the elderly, the screening and treatment of depression should be strengthened in the general elderly population.