MMN and P3a Elicited by a Novelty Oddball Paradigm Are Not Reduced in Early-Phase Psychosis

The present study compared the mismatch negativity (MMN) and P3a waveforms among early-phase psychosis (EPP; n = 13) individuals and healthy controls (n = 30) to contribute to the research on these waveforms as potential biomarkers for schizophrenia.MMN and P3a were elicited with a novelty paradigm using complex stimuli with electrophysiological technology.No significant group differences of amplitude were observed with either waveform. Increased asociality and blunted affect were associated with a reduction in both MMN and P3a waveforms indicating a relationship between these negative symptoms and cognitive deficits. Good social and occupational functioning correlated with improved MMN and P3a waveforms in the EPP group.This study suggests that MMN and P3a may be more appropriately used as an indicator of illness progression and symptomology rather than a biomarker in the early phase of the illness.