Linguistic analyses of speech disorder in psychosis

Much theory and research has been devoted to characterizing speech disorders in psychotic individuals and to understanding the connections between language productions and underlying cognitive processes. Studies in the literature have used primarily traditional clinical assessments and experimental task methods to study speech phenomena in psychotic patients. More recently, however, the range of study methods has expanded to include models based on normal language use, borrowed from the field of psycholinguistics. This article reviews linguistic studies of the discourse of psychotic patients with a focus on understanding speech disorders in the context of schizophrenia and mania. The studies are grouped according to the method of analysis used, including frequency counts, type-token ratios, cloze analyses, contextual constraint, pause and hesitation patterns, and discourse level analyses. Methodological problems and theoretical issues are summarised, followed by a statement of current status. The use of multiple measures applied to whole discourse speech samples offers particular promise for clarifying diagnostic issues and testing hypotheses based on cognitive models.