Indexed on: 17 Dec '04Published on: 17 Dec '04Published in: Psychiatry and Clinical Neurosciences
This study compared the effects of facial affective stimuli on visual event-related potentials (ERP) in schizophrenic patients and healthy subjects using photographs of babies depicting sadness (crying face), neutrality (neutral face), and pleasure (smiling face). Visual ERP were recorded using an oddball paradigm in 32 schizophrenic patients (16 paranoid type and 16 non-paranoid patients) and 32 age-matched healthy subjects. The P300 amplitude, latency, and the subject's reaction time were recorded. The P300 amplitude when viewing a photograph of a smiling baby was the smallest registered of three photographs for healthy subjects and paranoid type patients with successively greater amplitudes for neutrality and sadness. However, the P300 amplitude was the smallest while viewing crying photographs and was the largest while viewing a smiling photograph for non-paranoid patients. These results suggest that the P300 amplitude is influenced by viewing emotionally moving facial expressions and that the effect is different for different subtypes of schizophrenia. These differences may reflect differences in information processing resulted from emotional influences caused by visual-affective stimuli.