Hippocampus May Be Epicenter of Psychosis Brain Changes

Gray matter changes that occur across different stages of psychosis may begin in the hippocampus, suggest study results published in JAMA Psychiatry.

“This finding could potentially guide therapies that can target this area of the brain, potentially limiting the impact of the illness or perhaps even reducing the risk of psychosis onset,” said lead author Sidhant Chopra, PhD, of Monash University in Australia and Yale University in New Haven, Connecticut.

Researchers used magnetic resonance imaging (MRI) to investigate gray matter changes across different stages of psychotic illness in 534 people from 4 independent cohorts. Among patients with psychosis, 59 were antipsychotic-naïve with first-episode psychosis, 121 were within 3 years of psychosis onset, and 136 had established schizophrenia. Each group had a matched control group, comprising a total 218 patients.

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According to the study, gray matter alterations across different stages of psychotic illness were constrained by the underlying architecture of the brain’s axonal pathways.

“We found that the pattern of gray matter change seen in psychosis is not randomly distributed across the brain, but is shaped by a complex network of structural connections — in a very similar way to how we see the progression of neurodegenerative diseases in the brain,” Dr Chopra said.

Additionally, across all 4 patient cohorts, network diffusion modeling consistently identified the anterior hippocampus as a putative epicenter from which volume loss may spread to connected regions, researchers reported. The model accounted for both medication-related and illness-related changes.

“These findings suggest that white matter fibers may act as conduits for the spread of pathology across all stages of psychotic illness,” researchers wrote, “and medial temporal regions play a critical role in the origins of gray matter volume reductions.”

References

Chopra S, Segal A, Oldham S, et al. Network-based spreading of gray matter changes across different stages of psychosis. JAMA Psychiatry. 2023:e233293. doi:10.1001/jamapsychiatry.2023.3293

Scientists reveal how the effects of psychosis spread throughout the brain. News release. Monash University; September 20, 2023. Accessed September 25, 2023.