Use of reference markers in the speech of people with schizophrenia spectrum disorders: Evidence from two referential communication tasks manipulating common ground with the interaction partner.

Introduction: People with schizophrenia spectrum disorders present with language dysfunctions, yet we know little about their use of reference markers (indefinite markers, definite markers, pronouns or names), a fundamental aspect of efficient speech production. Methods: Twenty-five (25) participants with a recent-onset schizophrenia spectrum disorder (SZ) and 25 healthy controls (HC) completed two referential communication tasks. The tasks involved presenting to an interaction partner a series of movie characters (character identification task) and movie scenes composed of six images (narration task). A manipulation was introduced such that half of the movies could be considered as Likely-Known by the interaction partner, whereas the other half was Likely-Unknown. The analyses focused on the reference markers used to present the movie characters during the tasks. Results: During the character identification task, the SZ group used fewer names and more pronouns than the HC. During the narration task, the SZ group used fewer names and more definite references when initially introducing the main story characters, while no group effect emerged for subsequent mentions of the characters. The observed effects of conditions were generally present across both groups, except for a lesser adjustment in the use of definite markers when introducing the story characters. Conclusions: While some group differences emerged, people with SZ were generally sensitive to the manipulation regarding their interaction partner's likely knowledge of the characters. A better understanding of the conditions in which speech production is affected in SZ could help promote more efficient communication.