Neuropathological correlates of late-life depression in older people

Background Depression is common in old age and is associated with risk of dementia, but its neuropathological correlates in the community are unknown. Aims To investigate for the first time in a population-representative sample of people with no dementia the association between depression observed during life and neurofibrillary tangles, diffuse and neuritic plaques, Lewy bodies, brain atrophy and cerebrovascular disease found in the brain at post-mortem. Method Out of 456 donations to a population-based study, 153 brains were selected where donors had no dementia measured in life. Alzheimer and vascular pathology measures, Lewy bodies and neuronal loss were compared between those with (n = 36) and without (n = 117) depression ascertained using a fully structured diagnostic interview during life. Brain areas examined included frontal, parietal, temporal and occipital cortical areas as well as the entorhinal cortex, hippocampus and brain-stem monoaminergic nuclei. Results Depression was significantly associated with the presence of subcortical Lewy bodies. No association was found between depression and cerebrovascular or Alzheimer pathology in cortical or subcortical areas, although depression was associated with neuronal loss in the hippocampus as well as in some of the subcortical structures investigated (nucleus basalis, substantia nigra, raphe nucleus). Conclusions Late-life depression was associated with subcortical and hippocampal neuronal loss but not with cerebrovascular or Alzheimer pathology.