Comprehension of metaphor and irony in schizophrenia during remission: the role of theory of mind and IQ.

The study reported herein explored the comprehension of metaphor and irony in schizophrenia during remission, and examined the role of IQ and a theory of mind. Performance of 29 Schizophrenic patients in remission and 22 healthy controls was compared on metaphor and irony comprehension tasks and first- and second-order theory of mind tasks. Participants' IQs were measured using the Wechsler Adult Intelligence Scale-Revised, and the symptoms of individuals with schizophrenia were assessed using the Positive and Negative Syndrome Scale. The results showed that patients with schizophrenia were impaired in their comprehension of metaphor and irony as compared with healthy controls. A theory of mind deficit was found in patients with remitted schizophrenia. The comprehension of metaphor was significantly correlated with second-order false belief understanding and the comprehension of irony was not significantly related to theory of mind. IQ and verbal IQ did not explain the deficit of metaphor and irony comprehension. These findings were not explained by Happé's [Happé, F.G.E., 1993. Communication competence and theory of mind in autism: a test of relevance theory. Cognition 48, 101-119] theory and the shared semantic understanding requirement was discussed.