Diminished microstructural caudate asymmetry in schizophrenia spectrum disorders.

Hemispheric asymmetry is a fundamental feature of the healthy human brain, with consistent differences observed across individuals. However, disruptions in asymmetry are associated with a range of disorders, including schizophrenia. Large-scale studies reported subtle alterations in subcortical asymmetry in schizophrenia. However, these findings are primarily based on macrostructural measures, and the extent to which tissue-level changes occur remains unclear. In this work, subcortical microstructural asymmetry in schizophrenia was investigated using quantitative T1 (qT1) mapping. A total of 23 patients with schizophrenia spectrum disorders (SSD) and 12 healthy controls underwent 3T-MRI scanning. Asymmetry indices were calculated for several subcortical regions, and group differences were assessed using multiple linear regression, controlling for age and sex. A trend toward diminished caudate asymmetry in the SSD group compared to healthy controls was observed. However, this did not survive multiple-comparisons correction (β = 0.032, punadjusted = 0.01, pFDR = 0.07). Additionally, no significant relationships were found between asymmetry indices and symptom severity or antipsychotic dose equivalents. Our study shows a trend towards microstructural asymmetry in SSD, in line with the limited existing literature. These findings highlight the need for larger, well-powered studies to further elucidate the role of tissue-level asymmetry in the pathophysiology of SSD.