Brain Volume Reductions and Relationship With Depression and Cognitive Functioning in Suicide in Older Adults: A Cross-Sectional and Longitudinal Study Using Bayesian Multilevel Modeling.

Background: In older adults, depression with cognitive impairment may be a harbinger of early dementia and a risk factor for suicidal behavior. However, the neuroanatomical correlates of these impairments are unknown, particularly when examined longitudinally. Methods: Older adults ( Results: Three broad categories of individual differences emerged: 1) a history of attempted suicide and impaired executive functioning related to and predicted volumes in temporal areas, neighboring parietal and occipital regions, and the hippocampus; 2) frontal and subcortical volume reductions related to depression, particularly current episode severity; and 3) cognitive impairment typical of cortical dementia predicted medial temporal volume reduction. Conclusions: A history of suicidal behavior, depression, and dementia-related cognitive decline are accompanied by reduced brain volumes in largely non-overlapping regions that nevertheless converge on the hippocampus. The hippocampus may be a nexus where independent changes associated with depression and suicide diathesis factors co-occur with dementia-related neurodegeneration. These results support distinct neurocognitive deficits in late-life suicide in older adults. A better understanding of hippocampal structure and function in people at risk of suicide will advance both risk prediction and treatment development.