456. STRUCTURAL BRAIN DIFFERENCES IN INDIVIDUALS AT CLINICAL HIGH RISK FOR PSYCHOSIS

Abstract Background Schizophrenia (SCZ) is a severe mental illness that causes a substantial burden for individuals, families, and society. Early identification and intervention are crucial for improving patient outcomes. Prior to the onset of psychotic disorders, such as SCZ, individuals may go through a prodromal phase, known as clinical high risk for psychosis (CHR). Among those identified as CHR, the subtype termed attenuated psychosis syndrome (APS) is particularly significant, as it is associated with an increased risk of progression to psychosis and is commonly encountered in clinical practice. Although previous studies had reported structural brain differences in APS patients, no wide consensus has been reached. Aims & Objectives This study aimed to elucidate structural brain differences among APS, SCZ, and healthy controls (HCs) using structural magnetic resonance imaging (MRI) data, thereby advancing our understanding of the neurophysiological mechanisms underlying in APS. Method A total of 39 HCs, 38 APS, and 35 SCZ patients were finally included. T1-weighted MRI data were processed using SPM12 and CAT12 to quantify cortical thickness and gray matter volume (GMV) among the three groups were evaluated using analysis of covariance (ANCOVA), in which age, gender, years of education were regarded as covariates. The analysis was conducted using the Desikan-Killiany 40 template and the third version of the Automated Anatomical Labeling atlas. Voxel-level significance was set at P < 0.001, and False Discovery Rate correction was applied, yielding a cluster-level significance threshold of P < 0.05. Results Compared with HCs group, the APS and SCZ groups demonstrated a reduction in the cortical thickness in the left lateral occipital lobe. Compared with SCZ group, the APS and HCs groups exhibited a significant increase in the cortical thickness in some regions of the frontal and parietal lobes. Correlation analysis revealed that in the APS group, the thickness of the left triangular part of the inferior frontal gyrus and the right supramarginal gyrus exhibited significant negative correlations with reasoning and problem-solving ability scores. In the SCZ group, the cortical thickness of the left cuneus, inferior parietal lobule, and superior parietal lobule exhibited positive correlations with information processing speed scores. Additionally, compared with the SCZ group, the GMV in the frontal and insular regions was significantly increased in the APS and HCs groups. Discussion & Conclusions This study revealed significant differences in cortical thickness and GMV across specific brain regions among the HCs, APS, and SCZ patients, which may reflect underlying pathophysiological mechanisms of SCZ. Specifically, the reduced cortical thickness in the left occipital lobe may be associated with individual susceptibility to SCZ, while thinning cortical thickness in the frontal and parietal lobes, along with reduced GMV in the frontal and insular lobes, may be linked to the disease state of SCZ. The more widespread and severe damage to cortical thickness and GMV in SCZ patients compared with the APS, suggested a gradient pattern of brain structural impairment between the APS and SCZ patients.