T15. MISMATCH NEGATIVITY INDICES AS A PROGNOSTIC FACTOR FOR REMISSION IN SCHIZOPHRENIA

BACKGROUND: Mismatch negativity (MMN) is an event-related potential component when a sequence of relatively standard stimuli is interrupted by the infrequent presentation of deviant stimuli. MMN is known to be associated with neuro-cognition and functional outcomes. Also, abnormally decreased MMN has often been reported in schizophrenia. Remission and recovery rates are related to the neuro-cognition of patients with schizophrenia. The present study explored the relationship of MMN with remission in patients with schizophrenia. METHODS: Forty patients with schizophrenia were recruited and divided into two groups, with or without remission, according to the Remission in Schizophrenia Working Group criteria (RSWGcr). For assessments of symptom severity, cognitive function and functional outcome, scale such as Positive and Negative Syndrome Scale (PANSS), K-WAIS-IV, and Global Assessment of Functioning (GAF) were measured. MMN of the patients were evaluated at the frontocentral site. A regression analysis was used to identify the factors that significantly predicted symptom improvement and remission including MMN at frontal site assessed at baseline, and anticipated clinical variables as predictive factors. RESULTS: MMN amplitudes in frontal sites were further decreased in the groups without remission compared to the groups with remission. MMN amplitude was significantly correlated with measures of symptom change and functional outcome measurements in patients with schizophrenia. Regression analysis revealed that symptom severity and MMN significantly predicted remission in patients with schizophrenia. Symptom improvement significantly predicted PANSS at baseline, illness duration, and antipsychotic dose, as did MMN amplitude at frontal site. DISCUSSION: This study explored the relationship of MMN with remission in patients with schizophrenia. The remitted patients with schizophrenia showed larger MMN amplitude in frontal electrode site than those of non-remitted patients. MMN in frontal sites was correlated with symptom improvement and functional outcomes through PANSS and GAF scales. The present study found that MMN was significantly correlated with variables related to remission such as PANSS and GAF evaluated at 6 months later. MMN indexes appears to be a promising candidate for predicted factor of remission of schizophrenia.