How do people with schizophrenia explain the behaviour of others? A study of theory of mind and its relationship to thought and speech disorganization in schizophrenia.

BACKGROUND: This paper examines the attribution of mental states to others in schizophrenia and its links with thought and speech disorganization. METHODS: Two groups of schizophrenic subjects (15 with and 10 without thought and speech disorganization) were compared with 10 manic subjects and 15 normal controls on their pattern of answers to 14 theory of mind comic strips. RESULTS: Schizophrenic subjects with disorganization and a more severe general psychopathology exhibited more unadaptated interpretations of others' mental states than those without disorganization or the manic or normal controls. Their explanation of other people's behaviour tended to be influenced by the frequency of their actions rather than their mental states. CONCLUSIONS: The disorganization pattern in schizophrenia may be associated with a specific deficit of the cognitive ability referred to as theory of mind, and this deficit could be a state rather than a trait variable. Patients with thought and speech disorders may be more likely to understanding other people's mental states in unambiguous and common situations.