NEUROPHYSIOLOGICAL PROCESSING OF SOCIAL COGNITION: EEG EVIDENCE IN SCHIZOPHRENIA, BIPOLAR DISORDER, AND FIRST-DEGREE RELATIVES

Social and moral cognition influence sociability. Studies in healthy populations have shown that the evaluation of social outcomes modulates components such as the P2, the N400, and the late positive potential (LPP), reflecting early attentional processes as well as semantic and emotional integration. However, it remains unclear how these neurophysiological components operate in psychiatric populations, where one of the main alterations involves social cognition. The aim of this study was to examine the electrophysiological correlates of social outcome processing in patients within the psychotic spectrum, first-degree relatives, and healthy controls. High-density EEG (64 channels) was recorded while participants performed a reading task that manipulated the social profile of the protagonist (prosocial vs. antisocial) and the type of outcome (fortunate vs. unfortunate). Associated ERP components were analyzed. The results replicated the pattern previously described in healthy individuals. In contrast, patients within the psychotic spectrum (schizophrenia and bipolar disorder) showed an attenuation of the N400 component. First-degree relatives exhibited N400 modulations that were less pronounced than those of controls but more preserved than those observed in patients, suggesting the presence of a potential vulnerability phenotype. These findings suggest that the neurophysiological mechanisms involved in the evaluation of social outcomes are altered in the psychotic spectrum. The N400 component emerges as a potential early marker and a candidate risk endophenotype, contributing to a dimensional understanding of social cognition in psychiatry.