Social Support As a Protective Factor for Typically-Developing Siblings in the Presence of Parental Stress: A Moderated Mediation Model

Background: Typically-developing (TD) siblings of individuals with ASD may be at greater risk for negative outcomes due to a variety of factors, including symptom severity in siblings with ASD and elevated parental stress (Meadan et al., 2010). However, variability in sibling adjustment suggests that protective factors, such as social support, may improve TD sibling resilience (Armstong et al., 2005).  Unfortunately, the ways in which these factors interact to predict TD sibling outcomes remain poorly understood. 

Objectives: This study sought to examine social support as a possible buffer against TD sibling maladjustment within a moderated mediation model.  It was predicted that the indirect effect of symptom severity in siblings with ASD on maladjustment in TD siblings through parental stress would be moderated by TD sibling perceptions of social support.  Finally, exploratory analyses were conducted examining TD sibling maladjustment as predicted by social support subtypes. 

Methods: Participants included 113 parents and TD siblings [ages 11 to 17 (M = 13.34, SD = 1.81)] of a child with ASD [ages 3 to 17 (M = 12.03, SD = 3.28)].  Parents completed two Strength and Difficulties Questionnaires (SDQ; one on each child) to assess general emotional and behavioral functioning, the Children’s Social Behavior Questionnaire about the child with ASD to assess ASD symptom severity, and the Questionnaire on Resources and Stress – Short Form about themselves to assess parental stress.  TD siblings self-reported via the SDQ to assess their own functioning and the Child and Adolescent Social Support Scale to assess their perceived social support. 

Results: Conditional (based on TD sibling social support) indirect effects of ASD symptom severity on TD sibling maladjustment through parental stress were examined using bootstrapping analytical methods to estimate a bias-corrected asymmetric confidence interval of the indirect effects via “PROCESS,” a computational tool for SPSS (Hayes, 2013). The plotted significant interaction between parental stress and TD sibling social support shows that TD sibling social support is a protective factor in the presence of high parental stress (Figure 1). Furthermore, parental stress was more likely to mediate the relation between ASD symptom severity in siblings with ASD and TD sibling maladjustment when TD sibling social support was high, specifically leading to lower maladjustment under the high social support condition (Table 1). Additionally, parent- and self-reported TD sibling maladjustment were separately regressed onto TD sibling social support subtypes as simultaneous predictors after controlling for ASD symptom severity and parental stress.  Support from classmates (β = -.35, p = .01) and close friends (β = -.21, p = .03) uniquely predicted parent-reported TD sibling maladjustment, whereas support from parents (β = -.24, p = .02) and classmates (β = -.36, p = .01) uniquely predicted self-reported TD sibling maladjustment.     

Conclusions: TD sibling social support moderated the mediational relation among ASD symptom severity, parental stress, and TD sibling maladjustment. Results show the importance of social support in reducing TD sibling maladjustment when ASD symptoms and elevated parental stress are present and underscore the importance of considering multiple raters when assessing social support subtypes.