Broader Autism Phenotype Characteristics and Young Adults' Sibling Support

Background: Despite less frequent contact than at younger ages (e.g., White, 2001), young adults’ relationships with their siblings have important implications for relational and individual adjustment (e.g., Jensen et al., 2013). Given that siblings play important roles, as parents age, in caring for siblings with an autism spectrum disorder (ASD; Burke et al., 2012), it is critical to understand the nature of how young adult siblings support one another. In particular, examining how Broader Autism Phenotype (BAP) characteristics are associated with sibling support may aid in understanding these processes.

Objectives: The aim of this study was to examine associations between BAP characteristics in both young adults and their siblings, and the support young adults provide their siblings. Because of the gendered nature of sibling relationships and support (Kim et al., 2006), we examined whether patterns of support varied by young adults’ and their siblings’ sex.

Methods: Data came from a larger study about sibling influence in young adulthood, which included 873 young adults from across the United States, recruited through Amazon Mechanical Turk. Young adult participants were in their mid 20s (M age = 25.44, SD = 2.54) and had about two siblings (M = 2.23, SD = 1.49), were mostly female (56%), and Caucasian (73%). Participants reported their relationship with their closest aged sibling and up to two additional siblings (if applicable). In total, the 873 participants reported on tangible (financial and practical) and emotional (communication, discussing life, emotional assistance) support with 1,543 different siblings. Participants reported on their own BAP characteristics and those of each of their siblings via the Autism Spectrum Quotient (AQ; Baron-Cohen et al., 2001); 10 of the young adults and 27 of their siblings were reported to have a diagnosed ASD.

Results: Multi-level modeling was used to account for the nature of multiple relationships being nested within individuals. Separate hierarchical models were run for each dependent variable: tangible support, and emotional support. The models tested up to the three-way interactions of the young adults’ BAP characteristics X young adults’ sex X siblings’ sex, and the siblings’ BAP characteristics X young adults’ sex X siblings’ sex. Results revealed (see Table 1) that when young adults rated their sibling higher on the AQ, they reported giving more tangible support to that sibling, especially towards brothers. Females who rated themselves higher on the AQ also reported giving less tangible support to their brothers and sisters. Results also revealed (see Table 2) that individuals who rated themselves higher on the AQ reported giving less emotional support to their brothers and sisters.

Conclusions: These findings suggest that BAP characteristics in the general population, and not just ASD diagnosis, may play a role in the support siblings provide one another in young adulthood. In some cases, siblings may be aware of the needs of their brothers and sisters who show characteristics associated with ASDs, and may provide more tangible support to them. Those who report having more BAP characteristics themselves may not support their siblings in return