Executive Regulation of Speech Production in Schizophrenia: A Pilot Neuropsychological Study

Objective: To test the general hypothesis that schizophrenia patients have an executive deficit in speech production and the more specific hypothesis that this deficit is more severe when there is a greater demand on executive functions. Materials and methods: The study included 25 patients with schizophrenia and 27 healthy subjects (control group). All subjects took part in two tests: to tell stories based on a series of pictures and based on a specified theme. Results and conclusions: Schizophrenia patients displayed lower measures of programming and shorter texts and phrases than the control group in both tests. Patients’ subject-based stories included grammatical errors, along with the need for leading questions because of difficulties with plot construction; there was also greater dispersion of the length and syntactic complexity of the text. Thus, this study showed that during speech production, schizophrenia patients displayed a deficit of executive functions, which was most marked in the task involving a smaller number of external cues aiding speech planning and production.