Relationship between the social functioning of children with autism spectrum disorders and their siblings’ competencies/problem behaviors

Abstract

There is very little known about how sibling characteristics may influence the social functioning of a child with an autism spectrum disorder (ASD). The current study utilized data from the Simons Simplex Collection (SSC; n = 1355 children with ASD and 1351 siblings) to investigate this relationship. Phenotypic measures included (a) the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS), and the Vineland Adaptive Behavior Scales-II (VABS-II) for the probands with ASD and (b) the Social Communication Questionnaire (SCQ), the Social Responsiveness Scale (SRS), the Child Behavior Checklist (CBCL), and the VABS-II for siblings. Sibling data were first analyzed collectively, then analyzed by “older” and “younger” groups, relative to the age of the proband with ASD. Significant correlations were observed between probands’ and siblings’ VABS-II socialization domain scores; additional associations were noted between (a) probands’ VABS-II socialization domain scores and siblings’ CBCL internalizing subscale scores when only younger siblings were analyzed, and (b) probands’ ADOS Reciprocal Social Interaction (RSI) domain scores and the sibling SCQ scores when only older siblings were analyzed. These findings suggest that typically developing children may have a small yet meaningful influence on the prosocial development of their siblings with ASD. Limitations and future directions are discussed.

Introduction

It is well documented that sibling relationships can have both positive and negative influences on a child's development (Brody, 2004, Cicirelli, 1976, Deater-Deckard et al., 2002, Dunn, 1992). Abrams (2009) described siblings as “fellow travelers through the life cycle” who share a unique bond, which fosters development through close interaction, role playing, and sharing of emotions and experiences (p. 306). Approximately 80–90% of children grow up with a sibling (Dunn, 1992, Gass et al., 2007), so it is understandable how positive sibling relationships can prove extremely beneficial, even acting as buffers against different types of stress (Deater-Deckard et al., 2002, Gass et al., 2007). On the other hand, siblings may also cultivate negative experiences through rivalry, competition for parental attention, and aggressive behavior that may lead to subsequent conduct and/or behavior issues (Brody, 2004, Deater-Deckard et al., 2002).

However, what role do siblings play when one child has an intellectual or developmental disability? Just as with typically developing (TD) children, sibling interactions have been shown to play an influential role in the development of individuals with autism spectrum disorders (ASD) (Jones and Carr, 2004, Knott et al., 2007). Numerous studies have investigated the interaction between children with ASD and their unaffected siblings; this research has concentrated largely on the following three areas: the familiality of autism and sub-clinical qualities that may appear in siblings of children with ASD (August et al., 1981, Constantino et al., 2006, Silverman et al., 2002); the behavioral, emotional and/or social adjustment of unaffected siblings (Benson and Karlof, 2008, Hastings, 2003, Kaminsky and Dewey, 2002, Macks and Reeve, 2007, Pilowsky et al., 2004, Rodrigue et al., 1993); and the utilization of sibling-mediated social play with an affected child (Bass and Mulick, 2007, Tsao and Odom, 2006). However, there is very little research examining the role that siblings may play in terms of modeling or fostering pro-social behaviors and how this may influence the social functioning of their brothers/sisters with ASD.

Existing data indicate that siblings of children with ASD exhibit a different developmental trajectory compared to siblings of TD children. For example, Toth, Dawson, Meltzoff, Greenson, and Fein (2007) examined different characteristics (i.e. cognitive functioning, social communication skills, language abilities) of 42 TD siblings of children with ASD and 20 children with no family history of ASD; both groups ranged in age between 18 and 27 months and all siblings were younger than their counterparts with ASD. Using a combination of direct observation measures and parent report, the authors found that, overall, the 42 TD siblings of children with ASD demonstrated (a) lower levels of social communication and social-emotional functioning and (b) significantly lower expressive language and cognitive abilities compared to the control group. While the authors acknowledged that these results may demonstrate the expression of a genetic liability to ASD, they suggested that the deficits may also have been a result of environmental influences (i.e. having a sibling with ASD). Specifically, the investigators argued the possibility that close interaction with a brother/sister who suffers from varying degrees of social communication and language deficits (i.e. a sibling with ASD) may deter typical development in an unaffected child. Similarly, a study by Gamliel, Yirmiya, and Sigman (2007) found that, among the 39 participating siblings of children with ASD, 11 displayed a cognitive and/or language delay between 14 and 36 months of age; however, only two out of 39 siblings in the matched TD sample displayed a cognitive and/or language delay. With regard to other socio-emotional factors, studies have found that siblings of children with ASD display poorer adjustment when confronted by family stressors (i.e. divorce, maternal stress; Hastings, 2003), higher levels of internalizing and externalizing problems (Giallo and Gavidia-Payne, 2006, Rodrigue et al., 1993, Ross and Cuskelly, 2006, Verte et al., 2003), and fewer pro-social behaviors (Benderix and Sivberg, 2007, Kaminsky and Dewey, 2001).

In contrast, other researchers have found that, for some individuals, growing up with a sibling with ASD may have a positive or neutral effect on one's life. Macks and Reeve (2007) explored the psychosocial and emotional adjustment of 51 TD siblings of children with ASD compared to a sample of 35 siblings of non-disabled children, all between 7 and 17 years of age. Findings revealed that the siblings of children with ASD were more likely to view their own behavior, intelligence, scholastic achievements, and anxiety more positively than the siblings of non-disabled children. Another study by Pilowsky et al. (2004) examined different aspects of social and emotional development among 30 siblings of children with ASD, 28 siblings of children with intellectual disability (ID), and 30 siblings with developmental language disorders (DLD). While a total of 14 siblings from all three groups received various clinical diagnoses, the authors revealed that the siblings of children with ASD were reasonably well adjusted, according to various social and emotional measures, in that they found no differences in comparison with normative data or results from the ID and DLD samples. Other documented benefits of having a sibling with ASD are higher levels of maturity, well-rounded character, and an increased empathetic ability (Benderix and Sivberg, 2007, Lainhart, 1999, Pilowsky et al., 2004, Smith and Elder, 2010, Verte et al., 2003).

Investigators have explored potential relationship differences between older/younger sibling dyads. Earlier, researchers demonstrated that older female siblings were more effective instructors to their younger siblings compared to both (a) male siblings and (b) females who were teaching unrelated children (Cicirelli, 1972, Cicirelli, 1976). Additionally, other researchers have argued that older siblings (male or female) may influence their younger siblings’ language, motor skills, and social development by, theoretically, serving as an example to emulate (Berger and Nuzzo, 2008, Brody, 2004, Dunn and Shatz, 1989, Klein et al., 2002). Given that (a) older siblings operate in a semi-educational capacity for their younger counterparts and (b) younger siblings optimally benefit through sibling-mediated experiences versus those with unrelated children (Klein, Zarur, & Feldman, 2003), it is not surprising to see a growing body of research on the use of older siblings and peers as teachers/therapists for children with ASD (Trembath et al., 2009, Tsao and Odom, 2006).

Bass and Mulick (2007) performed a literature review of the various types of peer- and sibling-mediated social-intervention therapies and their benefits. They noted that siblings can, in fact, be effective trainers for their brothers/sisters with ASD; furthermore, having these trained siblings constantly engaging in positive social instructions and behaviors with the child with ASD (i.e. play-related speech, promoting response to initiation, integrating repetitive behaviors into games) resulted in increased social skills for the child with ASD that were generalized across settings. Similarly, a study conducted by Tsao and Odom (2006) enlisted four sibling dyads (one child in each dyad had an ASD) to investigate the effectiveness of a sibling-mediated intervention for children with ASD. In this intervention, the typical siblings – two of whom were older and two of whom were younger than the child with ASD – participated in a series of lessons that taught behavioral strategies for facilitating social interactions (i.e. initiating conversation, asking for help, maintaining eye contact); then, each sibling utilized the strategies when engaging in play with their siblings with ASD. Modest, positive changes in social abilities of the child with ASD in three of the sibling dyads were found. Although this study did not find evidence of cross-setting generalization of increased social skills, the authors suggested that increases in the number of intervention opportunities may increase the possibility of generalization across settings.

In summary, it is clear that sibling relationships play an important role in an individual's life. While there is an abundance of literature investigating typical sibling relationships, as well as outcomes for the siblings of children with ASD, there is significantly less known about how siblings’ characteristics may influence the social functioning of a child with ASD (i.e. examining the affected child's outcomes). Researchers have demonstrated that (a) positive sibling relationships may facilitate social development in children with ASD (Kaminsky and Dewey, 2001, Knott et al., 2007) and (b) siblings can be effective trainers via contrived therapeutic situations (Bass and Mulick, 2007, Tsao and Odom, 2006). But to what extent do TD children influence the social-skill development of their siblings with ASD in more naturalistic ways (i.e. in the absence of training)? Does the quality of the child's skills make a difference? It seems plausible that siblings who are socially adept could enhance the social-skill outcomes of their brothers/sisters with ASD by serving as positive, pro-social role models, whereas those who are less socially competent and/or exhibit some degree of psychopathology may not impart as many socially helpful cues to their affected counterparts. Yet, to our knowledge, neither of these notions has been explored. Thus, the current study aimed to investigate the relationship between siblings’ social competencies/problem behaviors and the social-skill functioning of their brothers/sisters with ASD.