Clustering and switching on verbal and nonverbal fluency in patients with schizophrenia

Abstract

In our study, we focus on the extent of occurrence of switching and clustering during fluency task among patients with schizophrenia compared to healthy controls. The previous studies found that both switching and clustering were affected in patients with schizophrenia. However, it has not clear yet if the decrease is caused by the impairment of executive functions or is related to poorer vocabulary. In our study, participants were tested Verbal Fluency Task (phonological and semantic) and also the nonverbal fluency task (measured by Five Point Test) so that the effect of vocabulary would be removed. Our study included 50 participants: 25 individuals with schizophrenia and 25 healthy controls. We found significant differences in the way of organization between group of psychiatric patients and healthy controls. The absence of clustering is typical for psychiatric population, patients tell the words without closer connection, they neglect association links, switch between clusters. Due to this way of response, they achieved lower score, they told fewer words than healthy controls. However, this manner was found also in nonverbal task where the patients did not follow one-way in drawing patterns and they often change the number of connecting dots or used lines. Our study implies that this condition is probably caused by disruption of the executive functions.

Disclosure of interest

The authors have not supplied their declaration of competing interest.