Cognitive disorders are frequently found during late-life depression (LLD). Many cognitive functions may be concerned and can be explained by frontostriatal brain circuits and hippocampus dysfunctions partly through abnormalities related to cerebrovascular diseases. It seems important to distinguish between early and late onset depression, the cognitive characterisation and aetiopathogenesis of which differ in some respects. Cognitive impairment may represent markers of depression, but it is still unclear whether potential biomarkers of disease should be considered as markers of condition, trait or risk factors. These disorders may precede depression and persist despite symptomatic remission. Moreover, the interest of specifying these disorders is multiple because they can have pejorative consequences, such as by modifying emotional content, encouraging suicidal acts, limiting the effectiveness of psychotherapy, being a risk factor for a poor response to antidepressants, or being a potential risk factor for progression to a minor or major neurocognitive disorder, especially Alzheimer disease.
Keywords: biomarker; cognitive decline; dementia; late-life depression; risk factor.