Reduced visual P300 amplitudes in individuals at ultra-high risk for psychosis and first-episode schizophrenia.

The purpose of this study was to investigate whether individuals at ultra-high risk (UHR) for psychosis and patients experiencing first-episode schizophrenia had impairments in visual information processing as indexed by the visual P300 event-related potential. Sixteen UHR individuals, 21 first-episode schizophrenia patients, and 16 healthy controls were included. Participants were asked to perform a visuospatial oddball task while undergoing an electroencephalogram. The UHR and first-episode groups showed reduced P300 amplitudes in comparison to healthy controls. P300 amplitudes were negatively correlated with severity of negative symptoms in both the UHR and first-episode groups. These results suggest that the visual P300 may be a neurobiological vulnerability marker, reflecting neurophysiological abnormalities associated with enduring negative symptoms in schizophrenia.