Study Finds Lower Hippocampus Volume in Patients With Psychosis

The Bipolar-Schizophrenia Network on Intermediate Phenotypes—consisting of institutions that include Harvard University, Wayne State University, and the University of Texas Southwestern—conducted a neuroimaging study in 549 patients with schizophrenia, schizoaffective disorder, or psychotic bipolar disorder to evaluate hippocampal volume in individuals with psychosis and the consequences of hippocampal volume as it relates to severity of the psychosis. The participants were compared with 337 healthy volunteers.

The results, published in JAMA Psychiatry, showed that volume in the hippocampus was significantly reduced in all three groups of patients with psychotic disorders when compared with that of controls. Reduced hippocampal volumes were correlated with worse psychosis severity, declarative memory, and overall cognitive performance.

“The causal mechanisms underlying psychotic symptoms are not well known,” Matcheri Keshavan, M.D. (pictured above), a professor of psychiatry at Harvard Medical School, told Psychiatric News in an interview. “The findings in this study point to the hippocampus…as a critical node on the network of brain regions that underlie the generation of psychotic symptoms such as delusions and hallucinations. Such understanding can help clinicians explain the nature of psychotic illnesses to patients and [their] families.” Keshavan concluded that more studies investigating the consequences of physiological and biochemical alterations in the hippocampus “are critically needed.”