A meta-analysis of deep brain structural shape and asymmetry abnormalities in 2,833 individuals with schizophrenia compared with 3,929 healthy volunteers via the ENIGMA Consortium

Abstract

Schizophrenia is associated with widespread alterations in subcortical brain structure.While analytic methods have enabled more detailed morphometric characterization,findings are often equivocal. In this meta-analysis, we employed the harmonizedENIGMA shape analysis protocols to collaboratively investigate subcortical brainstructure shape differences between individuals with schizophrenia and healthy con-trol participants. The study analyzed data from 2,833 individuals with schizophreniaand 3,929 healthy control participants contributed by 21 worldwide research groupsparticipating in the ENIGMA Schizophrenia Working Group. Harmonized shape analy-sis protocols were applied to each site's data independently for bilateral hippocam-pus, amygdala, caudate, accumbens, putamen, pallidum, and thalamus obtained fromT1-weighted structural MRI scans. Mass univariate meta-analyses revealed more-concave-than-convex shape differences in the hippocampus, amygdala, accumbens,and thalamus in individuals with schizophrenia compared with control participants,more-convex-than-concave shape differences in the putamen and pallidum, and bothconcave and convex shape differences in the caudate. Patterns of exaggerated asym-metry were observed across the hippocampus, amygdala, and thalamus in individualswith schizophrenia compared to control participants, while diminished asymmetryencompassed ventral striatum and ventral and dorsal thalamus. Our analyses also rev-ealed that higher chlorpromazine dose equivalents and increased positive symptomlevels were associated with patterns of contiguous convex shape differences acrossmultiple subcortical structures. Findings from our shape meta-analysis suggest thatcommon neurobiological mechanisms may contribute to gray matter reduction acrossmultiple subcortical regions, thus enhancing our understanding of the nature of net-work disorganization in schizophrenia.