Diminished humour perception in schizophrenia: relationship to social and cognitive functioning

This study attempted to confirm that humour recognition deficits previously found in schizophrenia are specific to the condition and not attributable to other parameters such as depression or anxiety. Secondarily, we explored any possible cognitive or social functioning correlates to humour recognition deficits. A total of 60 participants (20 outpatients with schizophrenia, 20 psychiatric control participants and 20 control participants) underwent a 64-question humour task in addition to a battery of standard cognitive tests and Social Functioning Scales. In order to compare the three groups of participants, we conducted an analysis of variance (ANOVA) and post-hoc t-tests on neuropsychological measures, social functioning measures, and the primary outcome, humour recognition. The schizophrenia group showed significant and substantial deficits in humour recognition compared to the healthy control group, t(38)=5.1, P<0.001, ES=-1.55 and the psychiatric control group, t(38)=3.6, P=0.001. In the schizophrenia group, humour recognition correlated positively with general intellectual functioning (NART) r=.45, P=0.04, social reasoning (WAIS-III Comprehension) r=.54, P=0.01, executive functioning (WCST-CC) r=.69, P=0.001 and social adjustment ratings (SASS scores), r=.54, P=0.02. These findings support the assertion that humour recognition deficits in schizophrenia are specific to the condition and not attributable to other factors such as depression or anxiety. Furthermore, humour recognition deficits in schizophrenia may perhaps be preferentially associated with deficiencies in set shifting and semantic cognition.