Relationship Between White Matter Microstructure and Hallucination Severity in the Early Stages of Psychosis: A Diffusion Tensor Imaging Study

Abstract

Background: Diffusion tensor imaging (DTI) studies have investigated the relationship between hallucinations in schizophrenia and white matter (WM) microstructure. However, only a few studies have focused on hallucination severity in the early stages of psychosis, and the involvement of the WM microstructure in the development of hallucinations remains unclear. This study aimed to examine the WM microstructure related to hallucination severity in the early stages of psychosis. Methods: DTI analysis using tract-based spatial statistics (TBSS) was applied to 138 participants, consisting of 105 individuals with early stages of psychosis (56 individuals with clinical high risk for psychosis [CHR] and 49 individuals with first-episode psychosis [FEP]) and 33 healthy controls (HCs). Group comparisons of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were performed. We examined the association of FA, MD, RD, and AD with hallucination severity in the early stages of psychosis. Results: Lower FA and higher MD and RD in multiple WM tracts were observed in the early stages of psychosis compared to HCs. We found an association between hallucination severity and increased MD in the WM tract, consisting mainly of the left superior longitudinal fasciculus (SLF) and inferior fronto-occipital fasciculus (IFOF). Conclusions: Our findings indicate that dysconnectivity in brain networks associated with language processing is related to the development of hallucinations. Further studies of the early stages of psychosis are needed to elucidate the mechanism of hallucinations.