Trait and state aspects of P300 in schizophrenia : a prospective longitudinal study

This study investigated trait and state aspects of the reduction of the P300 event-related potential component in schizophrenia in a prospective longitudinal design. Twelve patients and 12 healthy subjects underwent auditory and visual P300 tests on consecutive sessions at two month intervals. Patients had also PANSS symptom quantifications. The comparison between patients and healthy subjects revealed that the P300 reduction in patients is stable across sessions in the auditory modality thus representing a trait marker. The analysis of the relationships between symptoms and P300 showed that the frontal auditory P300 is negatively related to negative symptoms, whereas the posterior visual P300 positively correlates with positive symptoms. Consistent with clinical and pathophysiological models of schizophrenia, our study suggests that P300 assessment taking into account its frontal/posterior topography and visual/auditory modality could provide a simple tool to understand and follow changes in the brain activity involved in both trait and state expressions of schizophrenia