Specific linguistic and pragmatic deficits in Italian patients with schizophrenia

Abstract

Objective Verbal communication impairments are prominent features of schizophrenia. The grammatical and pragmatic components of expressive and receptive verbal abilities were systematically examined, for the first time, in Italian patients with schizophrenia. Indeed, most of the language literature is composed of studies on English speaking people. Method Elicited narrative production, and syntactic and pragmatic receptive abilities were analyzed in a cohort of 37 patients with schizophrenia and 37 healthy controls. Furthermore, a conversational speech production task was administered to an age- and gender-matched subset of this population. The level of significance was set at p ≤ 0.01. Results Participants with schizophrenia produced significantly less words on the narrative task and were less fluent on the conversational task than healthy controls. In both narrative and conversational speech they showed significantly poorer syntactic diversity skills. Errors at word level did not distinguish the two groups. At a receptive level, syntactic abilities were selectively impaired in patients with schizophrenia, who were also slower than controls in providing their answers. Metaphor and idiom explanations revealed consistent deficits in patients with respect to controls. Conclusions Reduced syntactic diversity characterized expressive language skills in schizophrenia. Syntactic abilities were selectively impaired also at the receptive level, suggesting an underlying processing deficit. On the pragmatic test schizophrenia patients were significantly less able to produce appropriate interpretations, indicating the presence of abnormal pragmatic inferential abilities. These findings confirm that language impairment is a key feature of schizophrenia independent of mother language and suggest a possible deficit involving hemispheric lateralization processes.