Hemispheric processing of idioms in schizophrenia and autism spectrum disorder

Studies conducted on individuals with schizophrenia (SZ) and autism spectrum disorder (ASD) show that they find it difficult to comprehend figurative language, and have a tendency to interpret it literally. This study examines hemispheric processing of idioms in patients with SZ, in comparison to individuals with ASD. Seventeen adults with SZ and 18 adults with ASD participated in the study. The two clinical groups were matched in age, vocabulary scores and verbal executive function scores. Using the divided visual field paradigm, the participants performed a lexical decision task for a target word related to either a literal or a figurative interpretation of an idiom. Whereas SZ patients showed the typical right lateralisation for non-salient literal interpretations of idioms, adults with ASD showed atypical bilateral processing. These findings indicate different hemispheric lateralisation in idiom processing in the two clinical groups.