Social judgement in clinically stable patients with schizophrenia and healthy relatives: behavioural evidence of social brain dysfunction

Background. Patients with schizophrenia have been found to display abnormalities in social cognition. The aim of the study was to test whether patients with schizophrenia and unaffected first-degree relatives of schizophrenic patients display behavioural signs of social brain dysfunction when making social judgements. Method. Eighteen patients with schizophrenia, 24 first-degree unaffected relatives and 28 healthy comparison subjects completed a task which involves trustworthiness judgements of faces. A second task was completed to measure the general ability to recognize faces. Results. Patients with schizophrenia rated faces as more trustworthy, especially those that were judged to be untrustworthy by healthy comparison subjects. Siblings of schizophrenia patients display the same bias, albeit to a lesser degree. Conclusions. The pattern of more positive trustworthiness judgements parallels the results from studies of patients with abnormalities in brain areas involved in social cognition. Because patients and siblings did not differ significantly from controls in their general ability to recognize faces, these findings cannot be dismissed as abnormalities in face perception by itself.