Quantitative assessment of attribution of intentions to others in schizophrenia using an ecological video-based task: a comparison with manic and depressed patients.

Schizophrenia is characterized by the impairment of several facets of social cognition. This has been demonstrated in numerous studies that focused on specific aspects of social cognition such as the attribution of intentions, emotions, or false beliefs to others. However, most of these studies relied on complex verbal descriptions or impoverished social stimuli. In the present study, we evaluated a new task (Versailles-Situational Intention Reading, V-SIR) that is based on video excerpts depicting complex real-life scenes of social interactions. Subjects were required to rate the probabilities of several affirmations of the intentions of one of the characters. The V-SIR task was administered to schizophrenic patients (N=15), depressed patients (N=12), manic patients (N=15), and healthy controls (N=15). The performance of schizophrenic patients was significantly impaired in comparison to healthy and depressed subjects. There was a trend toward a significant difference between schizophrenic and manic patients. Manic patients also demonstrated impaired performance relative to healthy subjects. Schizophrenic patients' V-SIR scores were significantly correlated with their scores on another attribution of intentions task that used comic strips. These results show that tasks based on more ecological stimuli are powerful enough to detect theory-of-mind abnormalities in pathological populations such as schizophrenic patients.