A Neuroanatomical Signature for Schizophrenia Across Different Ethnic Groups

Abstract

Schizophrenia is a disabling clinical syndrome found across the world. While the incidence and clinical expression of this illness are strongly influenced by ethnic factors, it is unclear whether patients from different ethnicities show distinct brain deficits. In this multicentre study, we used structural Magnetic Resonance Imaging to investigate neuroanatomy in 126 patients with first episode schizophrenia who came from 4 ethnically distinct cohorts (White Caucasians, African-Caribbeans, Japanese, and Chinese). Each patient was individually matched with a healthy control of the same ethnicity, gender, and age (±1 year). We report a reduction in the gray matter volume of the right anterior insula in patients relative to controls (P < .05 corrected); this reduction was detected in all 4 ethnic groups despite differences in psychopathology, exposure to antipsychotic medication and image acquisition sequence. This finding provides evidence for a neuroanatomical signature of schizophrenia expressed above and beyond ethnic variations in incidence and clinical expression. In light of the existing literature, implicating the right anterior insula in bipolar disorder, depression, addiction, obsessive-compulsive disorder, and anxiety, we speculate that the neuroanatomical deficit reported here may represent a transdiagnostic feature of Axis I disorders.

Keywords: ethnicity; magnetic resonance imaging; neuroanatomy; schizophrenia; voxel-based morphometry.

Fig. 1.

Region of the right anterior insula that showed reduced gray matter volume in patients relative to healthy controls consistently in each of the 4 datasets. The asterisk (*) indicates a statistically significant difference at P < .05 with Bonferroni correction for multiple comparisons. GMV = gray matter volume measured as mm³ of gray matter per voxel. 1 = Japanese; 2 = African-Caribbean; 3 = White Caucasian; 4 = Chinese.