Normal sexual dimorphism in theory of mind circuitry is reversed in Schizophrenia

Sex Differences in Cognition in Schizophrenia: What We Know and What We Do Not Know

Cognitive impairment is a core feature of schizophrenia. This selective review examines whether schizophrenia patients show preserved sexual dimorphism in cognition. Existing studies using performance tasks largely show comparable sex effects between schizophrenia patients and healthy populations. This pattern appears to be similar across multiple cognitive domains and across phase of illness. Our selective review also identifies several unresolved questions about sex differences in cognition in schizophrenia. A better understanding of sex differences in cognition in schizophrenia may provide important clues to probing the relationship between cognitive impairment and pathophysiological processes of the disorder.

Sex Differences in Social Cognition and Association of Social Cognition and Neurocognition in Early Course Schizophrenia

Background

Both impairment and sex differences in social cognition and neurocognition have been documented in schizophrenia. However, whether sex differences exist in the association between social cognition and neurocognition are not known. We aimed to investigate the contribution of areas of neurocognition to theory of mind (ToM) and hostility bias, representing social cognition, according to sex in early course schizophrenia.

Methods

In this cross-sectional study, we assessed neurocognition using the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS) and assessed the ToM and hostility bias subdomains of social cognition using the Social Cognition Screening Questionnaire (SCSQ) in 131 participants (65 female, 66 male) diagnosed with schizophrenia within 5 years of onset. Sex differences were analyzed using t-tests. The associations of neurocognitive subdomains with ToM and hostility bias according to sex were analyzed using multiple regression analysis. Results were adjusted by age, estimated premorbid intelligence quotient, and symptomatology.

Results

No sex differences were found in ToM (p = 0.071) or hostility bias (p = 0.057). Higher verbal fluency was significantly associated with higher ToM in females (p < 0.01), whereas higher executive function was significantly associated with higher ToM in males (p < 0.05). Higher verbal fluency was significantly associated with lower hostility bias in females (p < 0.05), whereas neurocognition and hostility bias were not significantly associated in males.

Conclusion

The results suggest that neurocognition associated with social cognition differ according to sex. These differences should be considered for more effective treatment of social cognition.