S46. IMPAIRED ERROR-PROCESSING IN PATIENTS WITH FIRST-EPISODE PSYCHOSIS: AN EVENT-RELATED POTENTIAL STUDY

BACKGROUND: Impaired error/conflict monitoring as reflected in the event-related potentials (ERPs) has consistently reported in patients with schizophrenia. However, whether this impairment exist from the early phase of psychosis such as first-episode psychosis (FEP) is not yet been clearly reported. To investigate the presence of error/conflict monitoring deficit in early psychosis, we examined the error-related negativity (ERN), error-related positivity (Pe), and correct-response negativity (CRN) during the Go/Nogo task in the patients with FEP. METHODS: 25 patients with and 25 age, sex matched healthy controls (HCs) were participated in electroencephalographic recording during the Go/Nogo task. Trials with error response was analyzed to define ERN at Fz electrode site and Pe at Pz electrode site. Trials with correct response was used for CRN analysis at Fz electrode site. Independent samples t-test was used to compare the amplitudes of ERP components between FEP and HC groups. Pearson’s correlation analysis was performed to reveal the relationship of altered ERP component with symptomatic severity in patients with schizophrenia. RESULTS: FEP patients showed significantly smaller ERN amplitude at Fz electrode site compared to HCs (t=-3.294, p=0.002). However, there was no difference of CRN (t=0.017, p=0.986) and Pe (t=1.806, p=0.077) amplitudes between FEP and HC groups. There was no significant correlation of symptomatic severity and ERN amplitude at Fz electrode site in FEP patients. DISCUSSION: These findings suggest that impairments in error/conflict monitoring as reflected by ERN amplitude exist from the early course of psychotic disorder. Future study with larger sample size and subjects at earlier phase such as clinical high risk for psychosis would be needed to confirm the findings of current study.