[Expressions of depression in Alzheimer's disease. The current scientific debate]

This overview analyses findings coming from researches that considered the interaction between depression and Alzheimer's disease (AD).

Information was collected from the Medline database and from a reasoned manual analysis of the published studies.

The prevalence of depressive symptoms in patients with AD is elevated (40-50%). The role of depression in the pathogenesis of AD (independent, prodromal symptom, factor of risk) still must be defined. Data on family history of depression suggest that AD could act as stimulus triggering depression from a basis of a genetic vulnerability. From a biological point of view the onset of depression could derive from an unbalance between cholinergic and noradrenergic systems. Psychological understanding sees depression as a reaction of mourning for the cognitive deficit. Current diagnostic instruments validated on patients with AD constitute a good aid for the clinician and the researcher. The identification of depression coexisting with AD is difficult, in absence of clear affective symptoms, since the cognitive, psychomotor and vegetative symptoms belong both to depression and to AD. The affective disorders most frequently reported are major depression and dysthymia. The use of antidepressant drugs with the lowest anticholinergic profile is strongly recommended. Good results have been obtained also using various psychotherapeutic interventions adapted for dementia sufferers.

The current scientific debate is based on information still limited and sparse. Future analyses should consider a better definition of the hypotheses related to psychopathology in AD, a standardised definition of cases and selection procedures and a prospective longitudinal design.