Theory of mind in schizophrenia: A critical review

INTRODUCTION: Frith's (1992) neuropsychological theory of schizophrenia posits a number of fundamental cognitive impairments underpinning the characteristic symptoms of this disorder. One of these is an impairment in the ability to correctly interpret and predict the mental states of other people, so-called theory of mind (ToM). There is already a substantial body of evidence that ToM is impaired in people with schizophrenia. Our aim was to critically review this literature. METHOD: A narrative review of the research literature was completed. Electronic searches of both Medline and PsycInfo were conducted to locate relevant articles. The bibliographies of relevant articles were scrutinised and in some cases researchers were contacted directly. RESULTS: A total of 30 studies that all examined some aspect of ToM in people with schizophrenia were located. These were summarised and key issues on this topic were identified. CONCLUSIONS: There is considerable evidence that ToM is impaired in people with schizophrenia. However, this is perhaps the only unequivocal finding on the topic to date. Issues that demand further clarification include: Is the deficit a state or a trait? How to measure ToM in schizophrenia research, and whether certain symptoms or groups of symptoms are associated with the ToM deficit. These issues are considered and the evidence evaluated. Some priorities for future research are suggested.