It’s Not About the Diagnosis: Sibling Relationships of Autistic and Non-Autistic Young Adults

Background: Positive sibling relationships have important implications for the well-being of autistic adults. Yet past research finds that individuals with autistic siblings report lower levels of sibling relationship quality. The research in this area, however, relies on the perspective of non-autistic family members and focuses on families where one sibling has a clinical autism spectrum disorder (ASD) diagnosis. The current study addressed these limitations by assessing whether autistic young adults also report poorer sibling relationship quality than non-autistic young adults and whether patterns differ by what it means to be autistic. Methods: Participants included a total of 964 18- to 29-year-olds ( M age = 24.61, SD = 2.90; 45% female; 58% White) from across the United States who completed an online survey. Participants were assigned to one of four groups: those diagnosed with autism or in the process ( n = 97), those who identify as autistic but have not been diagnosed and are not seeking diagnosis ( n = 80), those high in autistic traits but do not identify as autistic and have not been diagnosed ( n = 67), and the non-autistic ( n = 720). Results: Results show that young adults in the three autism groups reported poorer relationship quality than the non-autistic group in terms of closeness, conflict, ill-wishes, and parent-mediated relationships. Furthermore, autistic young adults reported greater heterogeneity in sibling relationship quality experiences (except for parent-mediated relationships) than non-autistic young adults. There were no mean or heterogeneity differences among the three autism groups on any relationship quality dimension. Conclusions: The findings suggested that autistic young adults report poorer sibling relationship quality than non-autistic young adults and that it does not matter if an individual has been clinically diagnosed with ASD; autistic traits are likely the driver of social experiences, not a diagnosis.