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

<b><i>Introduction:</i></b> The present study compared the mismatch negativity (MMN) and P3a waveforms among early-phase psychosis (EPP; <i>n</i> = 13) individuals and healthy controls (<i>n</i> = 30) to contribute to the research on these waveforms as potential biomarkers for schizophrenia. <b><i>Methods:</i></b> MMN and P3a were elicited with a novelty paradigm using complex stimuli with electrophysiological technology. <b><i>Results:</i></b> 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. <b><i>Conclusions:</i></b> 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.