Autism-spectrum quotient mediates the relationship between clinical symptoms and quality of life in schizophrenia

Background: Social dysfunctions can affect the quality of life (QOL) of patients with schizophrenia. The autism-spectrum quotient (AQ) is a widely used measure of innate autistic traits. However, in patients with schizophrenia, the score may represent the severity of autism-like social dysfunctions as a consequence of symptoms. We tested the hypothesis that AQ would mediate the relationship between clinical symptoms and QOL in patients with schizophrenia, based on the assumption that the AQ measures autism-like social dysfunctions rather than autistic traits in this population.

Methods: We analyzed data from 108 outpatients with schizophrenia. The relationships among the scores on the Positive and Negative Syndrome Scale (PANSS), the Schizophrenia Quality of Life Scale (SQLS), and the AQ were examined using structural equation modeling (SEM).

Results: Path analyses of the total scale scores revealed partial mediation, but not full mediation or independent effects. However, both the AQ and PANSS scores could be mediators. SEM including the three domain scores of PANSS, the two factors of the AQ, and the three subscale scores of the SQLS showed a good fit of the AQ mediation model, but not the symptom mediation model, supporting our hypothesis. In this final model, the relationship between negative symptoms and QOL was mediated by autism-like social dysfunctions, whereas positive symptoms directly affected QOL.

Conclusions: Our findings advance our understanding of what the AQ measures when applied to patients with schizophrenia and suggest that autism-like social dysfunctions are important treatment targets for improving QOL in this population.