Depression Tied to Shrinkage in a Key Memory Hub in the Brain

A USC-led study using MRI and PET scans of over 2,000 cognitively normal adults found that depression is linked to a smaller CA23DG portion of the hippocampus (comprising CA2/CA3 and the dentate gyrus), an association that largely held even after accounting for Alzheimer's risk factors. Antidepressant use and longer duration of depression were also associated with greater volume reductions in related hippocampal subregions, though the findings are correlational and do not establish causation or warrant changing treatment. Further longitudinal research is needed to understand the mechanisms at play.