Humour experience in schizophrenia: relationship with executive dysfunction and psychosocial impairment

The ability to appreciate humour is essential to successful human interactions. In this study, we hypothesized that individuals with schizophrenia would have diminished ability to recognize and appreciate humour. The relationship between humour experience and clinical symptoms, cognitive and social functioning was examined.

Thirty patients with a DSM-IV diagnosis of schizophrenia were compared with 30 age-, gender-, IQ- and ethnicity-matched healthy controls. Humour recognition was measured by identification of humorous moments in four silent slapstick comedy film clips and calculated as d-prime (d') according to signal detection theory. Humour appreciation was measured by self-report mood state and funniness ratings. Patients were assessed for clinical symptoms, theory of mind ability, executive function [using the Wisconsin Card Sorting Test (WCST)] and social functioning [using the Life Skills Profile (LSP)].

Patient and control groups did not differ in the funniness ratings they attributed to the video clips. Patients with schizophrenia had a lower d' (humour) compared to the controls, after controlling for (1) the performance of a baseline recognition task with a non-humorous video clip and (2) severity of depressive symptoms. In patients, d' (humour) had significant negative correlation with delusion and depression scores, the perseverative error score of the WCST and the total scores of the LSP.

Compared with controls, patients with schizophrenia were less sensitive at detecting humour but similarly able to appreciate humour. The degree of humour recognition difficulty may be associated with the extent of executive dysfunction and thus contribute to the psychosocial impairment in patients with schizophrenia.