The Moderating Role of Genetic and Environmental Risk Factors for Schizophrenia on the Relationship between Autistic Traits and Psychosis Expression in the General Population

Abstract

Background: Psychosis-related environmental risks in autism, along with genetic overlaps between autism and psychosis, have been well-established. However, their moderating roles in the relationship between autistic traits (ATs) and psychotic experiences (PEs) remain underexplored. Methods: First-wave data from 792 twins and siblings (mean age: 17.47±3.6, 60.23% female) in the TwinssCan Project were analyzed. PEs and ATs were assessed using the Community Assessment of Psychic Experiences and the Autism-Spectrum Quotient, respectively. Polygenic risk scores for schizophrenia and psychosis-Associated environmental factors (ie, childhood trauma (CT), bullying, negative life events, obstetric complications, cannabis use, winter birth, and hearing impairment) were tested for their independent effects on PEs and their interaction effects with ATs in moderating the relationship between ATs and PEs using separate multilevel linear regression models with Bonferroni's correction. Results: ATs, all CT subtypes, bullying, and negative life events were positively associated with PEs (all P<.004). Moderation analyses revealed that the association between ATs and PEs was amplified by emotional abuse (B:0.08, 95% CI, 0.05-0.11, P<.001), physical abuse (B:0.11, P=.001), sexual abuse (B:0.09, 95% CI, 0.03-0.15, P=.002), and physical neglect (B:0.06, 95% CI, 0.03-0.10, P=.001), emotional neglect (B:0.04, 95% CI, 0.01-0.07, P=.007), and negative life events (B:0.007, 95% CI, 0.0005-0.014, P=.04), although the latter 2 risks did not survive Bonferroni's correction. No significant main or interacting effects of genetic and other risk factors were found. Conclusions: People with high ATs were more likely to have PEs when exposed to CT. Trauma screening and early interventions might be warranted in this at-risk population.