Effect of antipsychotic on mismatch negativity amplitude and evoked theta power in drug-naïve patients with schizophrenia

Recurrent observations have indicated the presence of deficits in mismatch negativity (MMN) among schizophrenia. There is evidence suggesting a correlation between increased dopaminergic activity and reduced MMN amplitude, but there is no consensus on whether antipsychotic medications can improve MMN deficit in schizophrenia.

We conducted clinical assessments, cognitive function tests, and EEG data collection and analysis on 31 drug-naïve patients with schizophrenia. Comprehensive evaluation tools such as PANSS and MCCB. MMN amplitude was analyzed by event-related potential (ERP) approaches, evoked theta power was analyzed by event-related spectral perturbation (ERSP) approaches.

Our findings indicate that antipsychotic treatment significantly improved clinical symptoms, as evidenced by reductions in PANSS positive, negative, general symptoms, and total scores (all p < 0.001). Cognitive function improvements were observed in language learning, working memory, and overall MCCB scores (p < 0.05), although other cognitive domains showed no significant changes. However, no significant improvements were noted in MMN amplitude and evoke theta power after four weeks of antipsychotic treatment (p > 0.05).

These results suggest that while antipsychotic medications effectively alleviate clinical symptoms, their impact on MMN amplitude and evoke theta power deficit is limited in the short term. Moreover, the amelioration of cognitive impairment in individuals with schizophrenia is not readily discernible, and it cannot be discounted that the enhancement observed in language acquisition and working memory may be attributed to a learning effect. These findings underscore the complexity of the neurobiological mechanisms involved and highlight the need for further research to optimize individualized treatment strategies for schizophrenia.

ChiCTR2000038961, October 10, 2020.