The Moderating Role of Genetic and Environmental Risk Factors for Schizophrenia on the Association Between Autistic Traits and Psychosis Expression in a General Population Twin Sample

This study aimed to investigate the moderating role of genetic and environmental risk factors for psychosis on the relationship between autistic traits (AT) and psychotic-like experiences (PLEs) in the general population. We analyzed the first-wave data from twins and siblings participating in the TwinssCan Project (n=792). PLEs and AT were assessed using the Community Assessment of Psychic Experiences and the Autism-Spectrum Quotient, respectively. The main effects of polygenic risk scores for schizophrenia and individual psychosis-associated environmental risk factors (i.e., childhood trauma (CT), bullying, negative life events, obstetric complications, cannabis use, winter birth, and hearing impairment) and their interacting effects with AT were tested in separate models, using multilevel linear regression. Confirming prior literature, the results showed that AT, all five CT subtypes, bullying, and negative life events were significantly associated with PEs (all P < 0.004). The interaction analyses revealed that emotional abuse (B: 0.08, 95% CI:0.05 to 0.11, P < 0.001), physical abuse (B: 0.11, 95% CI: 0.05 to 0.18, P = 0.001), sexual abuse (B: 0.09, 95% CI: 0.03 to 0.15, P = 0.002), and physical neglect (B: 0.06, 95% CI: 0.03 to 0.10, P = 0.001) significantly amplified the positive relationship between AT and PEs, whereas emotional neglect (B: 0.04, 95% CI: 0.01 to 0.07, P = 0.007) and negative life events (B: 0.007, 95% CI: 0.0005 to 0.014, P = 0.04) only showed a trend of interactions. No significant main or interacting effects of genetic and other risk factors were found. Such findings imply that CT might be a potential preventive target for psychosis expression in people with high AT.