M134. MISMATCH NEGATIVITY IS REFLECTIVE OF DISEASE PROGRESSION RATHER THAN SYMPTOMATIC RECOVERY IN FIRST-EPISODE PSYCHOSIS

BACKGROUND: Whether mismatch negativity (MMN) is associated with clinical status or reflects the disease progression in first-episode psychosis (FEP) patients has not been established. We aimed to investigate whether the change in MMN impairment fluctuates with the change in clinical status during 1-year. METHODS: MMN and the clinical status of 25 patients with FEP were measured at baseline and reassessed after 1 year. MMN of 25 matched healthy controls (HCs) were measured at baseline. Repeated-measures analysis of variance (ANOVA) was used to compare MMN at baseline among the groups, and paired t-tests were utilized to compare baseline and 1-year MMN amplitude of FEP. To identify the association between MMN impairment change and symptomatic, cognitive or functional change during 1-year, this study used multiple regression analysis controlling possible confounders. RESULTS: MMN amplitudes at baseline were significantly attenuated in FEP patients compared to HC. One-year follow-up MMN amplitude decreased significantly at Fz electrode site in FEP group. Also, the change in MMN amplitudes significantly correlated with the worsened TMT-B but did not with the symptomatic or functional recovery. DISCUSSION: These results suggest that MMN impairment may be more closely related to cognitive deficits reflecting disease progression than the currently apparent symptoms and functional status during the beginning of a psychotic episode. Future studies are needed to elucidate the relationship with the disease pathophysiology of psychosis and MMN.