Expression and experience domains of negative symptoms in relation to social functioning in patients with schizophrenia: Results from a commonality analysis

Background Negative symptoms in schizophrenia are often conceptualized as comprising two domains, i.e., expression and experience, which have been associated with social functioning. However, whether these two negative symptom domains independently or jointly contribute to social functioning in this population remains unclear. Therefore, we investigated this issue by utilizing commonality analysis (CA). Methods Data were analyzed from 45 outpatients diagnosed with schizophrenia. Negative symptoms were assessed using the Positive and Negative Syndrome Scale, and social functioning was measured with the Specific Levels of Functioning Scale, which includes three subdomains: interpersonal relationships, activities, and work skills. Correlation analyses were conducted to examine the association between the expression and experience domains. Regression analyses were performed to predict the three subdomains of social functioning from the two negative symptom domains. Finally, CA was used to quantify their unique and shared contributions to social functioning. Results There was a significant positive correlation between expression and experience scores ( r = 0.52, p < .01). Regression analyses showed that expression scores were more strongly associated with the activities subdomain, and experience scores with the interpersonal relationships and work skills subdomains. CA revealed that a large proportion (≥ 0.48) of the explained variance in social functioning across subdomains was attributable to shared variance across the expression and experience domains. Conclusions These findings underscore the importance of assessing both aspects of negative symptoms when planning interventions for patients with schizophrenia. In particular, treatment targets may need to be tailored according to deficits in specific subdomains of social functioning.