Background: Several studies have revealed linguistic differences between diagnostic groups. This study investigates the extent to which these differences are accounted for by factors such as chronicity, or disturbances in cognition associated with acute psychosis.
Method: Transcripts of interviews with patients suffering from RDC schizophrenia (n=38), mania (n=11) and controls (n=16) were examined using the Brief Syntactic Analysis (BSA). Patients were within two years of first onset of psychotic symptoms, and received tests of working memory and attention.
Results: The speech of patients with schizophrenia was syntactically less complex than that of controls. Patients with schizophrenia and mania made more errors than controls. These differences were, to some extent, related to group differences in social class, working memory and attention, although significant group differences in language persisted after the effects of covariates were removed.
Conclusions: The study confirms the existence of differences in the speech of psychiatric patients. Low complexity appears to be a particular feature of speech in schizophrenia, even in the earliest stages of the condition. The importance of this finding is discussed in relation to two recent theories of schizophrenia: Crow's evolutionary model, and Frith's neuro-psychological model.