Psychosocial Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorder: Risk and Protective Factors

Background: Recent research has recognized the variability in outcomes for siblings of children with autism spectrum disorder (ASD). Given this variability, focus has shifted to identifying individual and family factors that may place some siblings at higher risk for experiencing psychosocial difficulties. Several recent studies have found support for a diathesis-stress conceptualization of sibling psychosocial difficulties. In this model, sibling broader autism phenotype (BAP) characteristics interact with family stressors to predict sibling difficulties. However, previous studies have used very small samples and have not examined the impact of these factors on the sibling relationship.

Objectives: This study aimed to investigate demographic factors (e.g., gender, birth order), sibling characteristics (e.g., BAP), and family stressors (maternal depression, child impact on family) in siblings of children with ASD (ASD-Sibs) and siblings of children with typical development (TD-Sibs) to identify risk and protective factors related to sibling behavioral and emotional adjustment and sibling relationship quality.

Methods: Mothers of ASD-Sibs (n=69) and TD-Sibs (n=93) completed online questionnaires about family demographics, sibling behavioral and emotional difficulties, sibling relationship quality, impact of the child on the family, and their own depressive symptoms. Sibling behavioral and emotional difficulties and sibling relationship quality were compared across groups. In addition, a series of MANOVAs and regression analyses were used to examine demographic and family factors that might predict which siblings were at higher risk for behavioral and emotional difficulties or poor sibling relationship quality.

Results: ASD-Sibs and TD-sibs demonstrated similar emotional and behavioral adjustment overall. ASD-Sibs demonstrated higher levels of prosocial behaviors compared to TD-Sibs. However, older brothers of children with ASD were at increased risk for difficulties compared to other groups of siblings. Sibling relationships of ASD-Sibs did not differ in overall level of positive or negative relationship behaviors. However, subscale-level patterns did differ between groups. Sibling relationships in ASD-Sibs involved less aggression, but also less involvement and more avoidance than those of TD-Sibs. Partial support for a diathesis-stress conceptualization of sibling difficulties was found for ASD-Sibs only. For TD-Sibs, broader autism phenotype (BAP) was related to psychosocial difficulties regardless of family stressors. For ASD-Sibs, BAP was related to psychosocial problems only when family stressors were also present.

Conclusions: These findings suggest that overall level of behavioral and emotional problems and sibling relationship quality is similar in ASD-Sibs and TD-Sibs. However, sibling relationship patterns may be qualitatively different in siblings of children with ASD. In addition, older brothers of children with ASD may be at increased risk for psychosocial difficulties. Finally, sibling broader autism phenotype characteristics were related to sibling adjustment and relationship difficulties. However, in the absence of additional family stressors, having a sibling with ASD appeared to confer a protective effect that reduced the negative impact of these BAP characteristics for the siblings. The researchers hypothesize that parents of children with ASD may have developed strategies for effectively coping with these characteristics in siblings due to their experience parenting their child with ASD.