Sibling relationship quality and psychosocial outcomes among adult siblings of individuals with autism spectrum disorder and individuals with intellectual disability without autism.

Research on adult typically-developing (TD) siblings of individuals with developmental disabilities remains limited, and outcomes for TD siblings appear to vary widely. For the current study, 82 adult TD siblings of individuals with autism spectrum disorder (ASD) or intellectual disability (ID) completed questionnaires about themselves and their affected sibling. Results of this study suggest that the attitudes possessed by adult TD siblings are important to consider when understanding adult TD sibling outcomes. Specifically, data indicate that higher levels of positive sibling relationship attitudes are related to TD siblings providing more aid/support to their sibling with a disability, along with having higher levels of general life satisfaction, and negatively related to levels of stress and depressive symptoms among TD siblings. Consistent with previous child research, siblings of individuals with ASD reported fewer positive sibling relationship attitudes compared to siblings of individuals with ID. Finally, group membership related to aid provided, depressive symptoms, and stress of TD siblings indirectly through sibling relationship attitudes. Overall, results indicate that sibling relationship attitudes may be particularly important to consider when conceptualizing sibling relationships when one sibling has an intellectual or developmental disability.