Depressive symptoms modify age effects on hippocampal subfields in older adults

Aim Major depression is associated with hippocampal volume changes, especially in late‐life depression. These changes usually consist of volume reductions, but depression‐related increases in hippocampal volume have also been reported. Subfield analysis has identified structural changes primarily in the cornu ammonis (CA) 1, CA2–3 and subiculum of the hippocampus in individuals with major depression; however, it is unclear whether lower levels of depressive symptoms are also associated volume reduction, or if depressive symptoms interact with age to impact hippocampal subfields. The current study addressed these questions. Methods A total of 43 community‐dwelling older adults completed the Center for Epidemiologic Studies Depression Scale and underwent magnetic resonance imaging. Hippocampal subfield segmentation was carried out using an automated procedure, and left and right volumes from CA1, CA2‐3, and the subiculum served as outcome measures. Multiple hierarchical regressions were carried out with age, Center for Epidemiologic Studies Depression Scale scores and their interaction as the independent variables, and sex and total intracranial volume as covariates. Results Higher Center for Epidemiologic Studies Depression Scale scores were associated with less age‐related volumetric decreases in the right subiculum and right CA1. Conclusions Age‐related atrophy in the hippocampus might be counteracted by depressive symptom‐related enlargement of CA1 and the subiculum. More research is required to better understand the functional significance of this relationship. Geriatr Gerontol Int 2017; 17: 1494–1500.