Depression with anosognosia following a left subcortical stroke.

Controversy exists about whether depression following stroke represents a biologically mediated change or a psychological reaction to the deficits. We present a patient with an acute isolated personality change and depression following a lacunar infarct of the left internal capsule, who was unaware of his affective change. His anosognosia for the depression, which was abrupt and not accompanied by cognitive impairments, suggests that post stroke depression, at least in this case, is better explained by a biological than a psychological model.