Hippocampal Volume Tied to Psychotic Disorders

HealthDay News — Hippocampal volumes are reduced in patients with psychotic disorders compared with healthy controls, according to researchers.

“Hippocampal subfields that participate in memory-related processes supporting pattern separation and pattern completion might be abnormal and may underlie the pathophysiology of psychosis,” Matcheri S. Keshavan, MD, of the department of psychiatry at Beth Israel Deaconess Medical Center and Harvard Medical School, both in Boston, and colleagues reported in JAMA Psychiatry.

They analyzed neuroimaging studies from a large series of probands with psychotic disorders and healthy volunteers. Participants were part of the Bipolar-Schizophrenia Network on Intermediate Phenotypes and included 219 patients with schizophrenia, 142 patients with schizoaffective disorder, 188 patients with psychotic bipolar disorder and 337 healthy controls. 

The researchers found that hippocampal volume reductions were seen in all three diagnostic groups, compared with healthy controls. Significant changes in the entorhinal cortex and parahippocampal regions were only seen with schizophrenia and schizoaffective disorders (P<0.001).

All three psychotic disorders were also associated with smaller volumes across the hippocampal subfields, with the most prominent differences being in cornu ammonis 2/3 (P<0.001). There was a positive correlation between hippocampal volumes and psychosis severity, declarative memory, and overall cognitive performance (P<0.05).

“Hippocampal subfields that participate in memory-related processes supporting pattern separation and pattern completion might be abnormal and may underlie the pathophysiology of psychosis,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.