Alterations in the hippocampus and thalamus in individuals at high risk for psychosis

• Published in: NPJ schizophrenia 2016-09, Vol.2 (1), p.16033-16033, Article 16033
• Main Authors: Harrisberger, Fabienne, Buechler, Roman, Smieskova, Renata, Lenz, Claudia, Walter, Anna, Egloff, Laura, Bendfeldt, Kerstin, Simon, Andor E, Wotruba, Diana, Theodoridou, Anastasia, Rössler, Wulf, Riecher-Rössler, Anita, Lang, Undine E, Heekeren, Karsten, Borgwardt, Stefan
• Format: Article
• Language: English
• Subjects: 631/378/1689/1761; 692/53; Cognitive Psychology; Medicine; Medicine & Public Health; Neurology; Neurosciences; Psychiatry; Psychosis
• ISSN: 2334-265X; 2334-265X
• DOI: 10.1038/npjschz.2016.33

Reduction in hippocampal volume is a hallmark of schizophrenia and already present in the clinical high-risk state. Nevertheless, other subcortical structures, such as the thalamus, amygdala and pallidum can differentiate schizophrenia patients from controls. We studied the role of hippocampal and subcortical structures in clinical high-risk individuals from two cohorts. High-resolution T 1 -weighted structural MRI brain scans of a total of 91 clinical high-risk individuals and 64 healthy controls were collected in two centers. The bilateral volume of the hippocampus, the thalamus, the caudate, the putamen, the pallidum, the amygdala, and the accumbens were automatically segmented using FSL-FIRST. A linear mixed-effects model and a prospective meta-analysis were applied to assess group-related volumetric differences. We report reduced hippocampal and thalamic volumes in clinical high-risk individuals compared to healthy controls. No volumetric alterations were detected for the caudate, the putamen, the pallidum, the amygdala, or the accumbens. Moreover, we found comparable medium effect sizes for group-related comparison of the thalamus in the two analytical methods. These findings underline the relevance of specific alterations in the hippocampal and subcortical volumes in the high-risk state. Further analyses may allow hippocampal and thalamic volumes to be used as biomarkers to predict psychosis. Early detection: Structural brain changes in at-risk individuals People at high risk of developing schizophrenia have detectable changes in the size of key brain structures, say researchers in Switzerland. The volume of the hippocampus, a brain region associated with learning and memory, is known to be smaller in schizophrenics and individuals who are at high risk of developing psychosis, but anatomical changes in other brain structures are less well documented. A team led by Fabienne Harrisberger at the University of Basel performed MRI scans on 91 high-risk individuals and 64 healthy controls and found that the volumes of two brain structures, the hippocampus and thalamus, were reduced in the at-risk group. Not everyone in this high-risk state goes on to develop schizophrenia, so it is hoped that this finding can be adapted to help predict those most likely to become ill.