244. ABNORMALITIES OF SUBCORTICAL BRAIN VOLUME THROUGHOUT THE PSYCHOSIS COURSE

Abstract Background Previous studies have indicated abnormalities within subcortical brain morphology among schizophrenia patients. However, it remains unclear when the morphology change emerges, and whether the usage of antipsychotic could account for this structural change. Aims & Objectives The purpose of this study is to explore the subcortical morphology in three timepoints: early psychosis before initial treatment, 28 days after initial treatment, and chronic schizophrenia after long-term usage of antipsychotics. Method Thirty early psychosis patients meeting the diagnostic criteria for Ultra-High Risk, First Episode Psychosis, schizophreniform disorder, or First Episode Schizophrenia and 93 patients meeting the DSM-IV schizophrenia criteria were recruited from the outpatient clinics of the Department of Psychiatry in National Taiwan University Hospital. Thirty healthy controls and 100 healthy controls for comparison of early psychosis patients and chronic schizophrenia patients were recruited from hospital staff and community. The early psychosis patients were either antipsychotic-naïve or had received antipsychotics for less than 12 weeks before recruitment. The chronic patients received stable dose of antipsychotics. After recruit, the early psychosis patients received flexible-dose aripiprazole. Clinical symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) at day0, 14 and 28 for the early psychosis patients, and at recruit time for the chronic schizophrenia patients. The average treatment duration between baseline and follow-up fMRI scans was 41.57 ± 13.93 days for the early psychosis patients. For the chronic schizophrenia patients, fMRI was assessed at recruit time. Subcortical volumes were obtained from the automated procedure for volumetric measures of subcortical brain structures. ANCOVA (age, sex, education, and ICV as covariates) was employed to investigate volumetric group differences in subcortical brain regions. Results Compared with the healthy participants at recruit time, the early psychosis patients showed smaller subcortical volume in left thalamus (F=4.14, p<0.05) and right putamen (F=6.20, p<0.05). Also, there was a negative correlation between volume of left thalamus and PANSS total score (r=-0.51, p<0.01), disorganized thought (r=-0.45, p<0.05), and negative dimension (r =-0.59, p<0.001) in early psychosis. After treatment with aripiprazole for 28 days, the structural difference was no longer observed. No significant correlation was identified between the subcortical volume and clinical symptoms after initial treatment, either. In chronic schizophrenia, patients had smaller bilateral hippocampus (F=16.32, p<0.001; F=18.22, p<0.001) and larger bilateral pallidum (F=13.32, p<0.001; F=17.31, p<0.001) than the healthy controls. Also, the volumes of left and right thalamus were negatively correlated with the negative dimension (r=-0.31, p<0.01; r=-0.26, p<0.01). Discussion & Conclusions Our study illustrated the subcortical change throughout the illness course of schizophrenia. Subcortical alterations were already observed in early psychosis but resolved after initial treatment. In chronic schizophrenia, smaller hippocampus and larger pallidum were observed. The thalamus volume was associated with clinical symptoms at early and chronic stage. Enlarged basal ganglia was noted along with the increase exposure of antipsychotics. The current study has shed light on the subcortical volume pattern throughout the illness course of schizophrenia. Future studies should focus on the role of subcortical volumes as biomarkers for symptoms prediction and identify the influence of illness course and antipsychotics exposure on subcortical volumes.