Hippocampal Subregions Across the Psychosis Spectrum

• Published in: Schizophrenia bulletin Vol. 44; no. 5; pp. 1091 - 1099
• Main Authors: Vargas, Teresa, Dean, Derek J, Osborne, Kenneth Juston, Gupta, Tina, Ristanovic, Ivanka, Ozturk, Sekine, Turner, Jessica, van Erp, Theo G M, Mittal, Vijay Anand
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 20-08-2018
• Subjects: Adolescent; Adult; Cognitive Dysfunction - diagnostic imaging; Cognitive Dysfunction - etiology; Cognitive Dysfunction - pathology; Cognitive Dysfunction - physiopathology; Cross-Sectional Studies; Disease Progression; Female; Hippocampus - diagnostic imaging; Hippocampus - pathology; Hippocampus - physiopathology; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Prodromal Symptoms; Psychotic Disorders - complications; Psychotic Disorders - diagnostic imaging; Psychotic Disorders - pathology; Psychotic Disorders - physiopathology; Regular; Risk; Schizophrenia - complications; Schizophrenia - diagnostic imaging; Schizophrenia - pathology; Schizophrenia - physiopathology; Young Adult; psychosis spectrum; hippocampal subregions; medial-temporal function; cognition
• ISSN: 0586-7614; 1745-1701; 1745-1701
• DOI: 10.1093/schbul/sbx160

Abstract
Introduction
Converging evidence suggests that hippocampal subregions subserve different functions, and are differentially affected by psychosis illness progression. Despite this fact, studies have not often studied subregions cross-sectionally across the psychosis spectrum. Furthermore, little is known about associations between subregion volumes and hippocampus-mediated cognition.
Methods
A total of 222 participants (61 ultra high risk [UHR], 91 schizophrenia [SCZ], and 70 healthy volunteers) underwent a 3T MRI scan, as well as structured clinical interviews and a cognitive battery. Hippocampal subfield analysis was conducted with Freesurfer. We compared subregion volumes across groups, controlling for age, gender, and intracranial volume. We also examined associations in the UHR and SCZ groups between hippocampal subregion volumes and verbal learning, visual learning, and working memory.
Results
We found a dose-dependent relationship such that the SCZ group showed significantly greater subfield volume reductions than the UHR group, which in turn showed significantly greater subfield volume reductions than the healthy volunteer group. We also found associations between subregion volume and cognitive performance in the visual memory, verbal memory, and working memory domains.
Discussion
Our study examined hippocampal subregion volumes cross-sectionally in a large sample across the psychosis spectrum, as well as links with hippocampus-mediated cognitive function. Our findings suggest that hippocampal abnormalities emerge before first psychosis episode onset, and may be etiologically informative.