Visual emotional information processing in male schizophrenia patients: Combining ERP, clinical and behavioral evidence

We used event-related potentials (ERPs) to examine the time course of visual emotion processing in schizophrenia. ERPs were recorded in 19 chronic male schizophrenia patients and 16 healthy controls (HC) while they viewed IAPS pictures used to induce positive, negative, or neutral mood, presented in a blocked design across three separate occasions. Electrophysiologically, groups differences were found in early potentials (the first 200 ms of picture viewing): C1, P1, and N1; also, less positive, broadly distributed P2 was found in the patient group. P2 amplitude to negative valenced pictures only was correlated with self-reported negative mood in the patients. The groups did not differ in late-occurring potentials, specifically the late positive potential (500-1000 ms latency window). Patients reported more negative affect before and after the three types of mood induction; however, mood induction influenced both groups in the same direction. Both groups showed similar subjective valence and arousal ratings of evocative stimuli. The ERP results suggest that visual evocative stimuli are differentially processed within the first 200 ms, and that the early stages of visual evocative stimuli processing are abnormal in schizophrenia, irrespective of stimulus valence. The correlation found between sensory abnormalities in negative pictures processing and negative mood suggests a relationship between abnormal sensory processes and increased negative mood experience in patients.