Pragmatic language and theory of mind deficits in people with schizophrenia and their relatives

Background: Deficits in theory of mind have frequently been observed in people affected by illnesses characterized by disrupted social behaviour like autism and psychoses. In schizophrenia, a pragmatic deficit in expressive language can also be observed. The present study was designed in order to assess the suitability of theory of mind and pragmatic conversation abilities as possible cognitive endophenotypes of schizophrenia. Methods: First- and second-order false belief tasks and pragmatic deficits in expressive language were examined in 38 patients with schizophrenia, in 34 non-psychotic relatives and in 44 healthy controls. An extensive clinical and neuropsychological assessment was also conducted. Results: Schizophrenic people and their first-degree relatives performed worse than the normal control subjects in false belief and pragmatic conversation tasks. General cognitive ability and neuropsychological measures of executive functions were not related to social cognition tasks. Conclusions: Theory of mind disorders and failing to understand the gricean conversational maxims are associated with schizophrenia liability. Copyright (C) 2008 S. Karger AG, Basel.