Anosognosia and Alzheimer's disease: the role of depressive symptoms in mediating impaired insight.

The relation between anosognosia and dementia severity in Alzheimer's disease (AD) has been unclear. We constructed a measure that quantified the difference between the perceptions of deficits of patients with AD (n = 23) and ratings from a knowledgeable informant as a measure of anosognosia. There was no correlation between dementia severity and anosognosia. However, dementia severity was positively correlated with the degree of anosognosia after controlling for depressive symptomatology (p =.03). Post-hoc analyses, also controlling for depressive symptoms, indicated that higher levels of anosognosia were associated with lower performance on specific cognitive tasks. These results suggest depressive symptoms may confound the relationship between anosognosia and dementia severity.