A Family Affair: Identifying and Examining Risk Factors for the Emotional and Behavioral Adjustment in Siblings of Children with Autism

Background:  Sibling relationships are known to have a significant impact on the process of social and emotional development (Dunn, 1988).  A number of studies have focused on the sibling relationship and the potential challenges faced by typically developing (TD) siblings of children who have an autism spectrum disorder (ASD) (Gold, 1993; Knott, Lewis & Williams, 1995; Hastings, 2003; 2007; Orsmond & Seltzer, 2007, 2009; Benderix & Sivberg, 2007; Petalas & Hastings, 2009).  This study sought to examine how family demographic variables as well as behavioral characteristics of children with ASD impact the adjustment of their TD siblings.

Objectives: To identify and examine potential demographic and behavioral risk factors for the social, emotional and behavioral adjustment of TD siblings of children with ASD. 

Methods:  A sample of 2109 sibling pairs was drawn from the Simons Simplex Collection and the Boston Autism Consortium for use in the current project. Age ranges included children with ASD and their TD siblings between the ages of 4 to 18.  To verify ASD diagnosis, the Autism Diagnostic Observation Schedule (ADOS) and Autism Diagnostic Interview-Revised (ADI-R), were performed.  To confirm neurotypical development in the unaffected child, parents were asked to provide medical and educational information.  Parents completed measures to characterize the emotional and behavioral development of both children, including the Child Behavior Checklist (CBCL), and the Vineland Adaptive Behavioral Scales-II (VABS-II). In addition, parents provided demographic and familiar relations information. Preliminary analyses focused on testing the following demographic and behavioral risk factors: age and gender of sibling with ASD, NVIQ of child with ASD, and parent marital status. MANOVAs were peformed to examine the impact of these variables on the TD sibling’s CBCL and VABS-II scores. 

Results:  Analyses focused on the age of the child with ASD indicated that being younger than a sibling with ASD results in significantly higher scores on the following CBCL scales: rule-breaking, aggressive, externalizing problems, total problems, oppositional defiant problems, and conduct problems. Having a male sibling with autism resulted in significantly lower scores for the TD sibling on VABS communication and composite domains, as well as significantly higher scores on the attention subscale of the CBCL. Also, having a lower functioning sibling (in terms of NVIQ) resulted in significantly higher scores for TD siblings on the following CBCL subscales: somatic complaints, rule-breaking, aggressive, internalizing problems, externalizing problems, total problems, somatic problems, oppositional defiant problems, and conduct problems. TD children of divorced parents had significant scores on the somatic complaints, rule-breaking and conduct problems subscales. 

Conclusions:  Children who have a sibling with ASD who is  male, older, and functioning at a lower level have a higher prevalence of social, emotional, and behavioral difficulties, particularly externalizing behaviors such as aggression, defiance, and attention problems.  Future analyses will aim to further clarify the relationship between characteristics of children affected with ASD, family dynamics, and other demographic variables on the development of TD siblings.