Absence of effect of depression on cognitive performance in early-stage Alzheimer disease.

Background: Depression can interfere with the normal expression of cognitive abilities in adults of all ages, but it is unclear if depression in demented people, which is common, is associated with reduced cognitive performance beyond the effect of the dementia itself.

Objective: To determine if depression adds to the cognitive deficit in dementia.

Design: Performance on psychometric tests of memory and other cognitive function was correlated with the number of depressive features reported by the individual and by a knowledgeable collateral source, as well as the judgment of a research clinician as to whether the person was depressed.