Hippocampal volume and incident dementia in geriatric depression.

The authors investigated the role of baseline hippocampal volume on later clinical emergence of dementia in a group of older, non-demented depressed individuals. Subjects were 115 depressed, non-demented participants in a mental health clinical research center. All subjects were screened for dementia and agreed to have a magnetic resonance imaging (MRI) brain scan at baseline. Subjects were clinically evaluated by geriatric psychiatrists quarterly for up to 5 years and received annual neuropsychological testing. Bivariate analyses examined age, gender, race, educational level, baseline depression severity, age at depression onset, baseline Mini-Mental State Exam (MMSE), left and right hippocampal volume, and total cerebral volume. Age, baseline MMSE, total cerebral volume, and having a small left hippocampal volume were associated with later dementia and were included in subsequent survival analysis. Small left hippocampal volume was significantly associated with later dementia (hazard ratio=2.762). Small left hippocampal size on neuroimaging may be a marker for dementia in depressed patients who have not yet met criteria for a clinical diagnosis of a dementing disorder.