Social cognition in schizophrenia: similarities and differences of emotional perception from patients with focal frontal lesions.

The structural and functional abnormalities of the frontal lobes, the region implicated in social information processing, have been suspected to underlie social cognitive impairments in schizophrenia. However, multiple structures, including the limbic/paralimbic areas that are also important for social cognition, have been reported to be abnormal in schizophrenia. The aim of this study is to investigate the extent to which the frontal lobe dysfunction accounts for social cognitive impairments in schizophrenia by comparing with patients who have focal frontal lobe injuries. Social cognitive abilities, focusing on affective aspects, were examined by an emotion intensity recognition task, which is sensitive to the amygdala function, and the emotion attribution tasks, which rely mainly on the frontal lobe function. Individuals with schizophrenia were impaired on the emotion intensity recognition task as well as on the emotion attribution tasks as compared with healthy subjects. By contrast, the frontal lobe-damaged group was defective in the emotion attribution tasks but not in the emotion intensity recognition task. Our results indicated that social cognitive impairments observed in schizophrenia can be accounted for partly by their frontal lobe pathology. Other aspects of social cognitive impairments could also be associated with the extra-frontal pathology, such as the amygdala.