Hippocampal subfield volumes and memory deficits in schizophrenia

Schizophrenia is a debilitating disorder commonly associated with significant cognitive impairment, particularly in memory. Reduced gray matter volume in various brain regions, including hippocampus and its subfields, is also well-documented in individuals with schizophrenia (SZH). However, few studies have investigated how memory deficits relate to hippocampal subfield volume deficits.

In this study, we examined hippocampal subfield volumes and their associations with immediate and delayed memory performance (using the WMS-III battery), comparing 57 individuals with SZH to 32 well-matched controls.

Compared to controls, SZH exhibited lower memory performance, and lower hippocampal volumes, particularly in the left hippocampus and the CA1 and parasubiculum subfields. Both Immediate and Delayed Free Recall memory performance positively correlated with left CA1 volume in SZH only, and not in controls. Positive associations were also observed between Thematic Recall scores and volumes in the left CA1, CA3, and CA4/DG subfields in SZH only, but only at an uncorrected threshold.

These findings provide evidence that hippocampal volumetric alteration contributes to memory impairment in SZH. In particular, findings highlight the importance of the left CA1 subfield, as we identified volumetric associations with memory performance that were unique to SZH. These mechanistic insights inform potential targeted intervention strategies to address memory impairment and promote functional recovery in SZH.