Individuals with autism spectrum disorders (ASD) undoubtedly exhibit social-skill deficits, but the range of social-skill functioning can vary drastically from one affected child to the next. Just as with typically developing children, sibling interactions have been shown to play an influential role in the development of children with ASD (Jones & Carr, 2004; Knott, Lewis, & Williams, 2007; Murray et al., 2008). However, most studies have focused on the proband’s outcomes given the presence of an interactive sibling, and less is known about how sibling attributes may influence the social-skill functioning of the proband. It seems plausible that siblings who are less socially competent and/or exhibit some degree of psychopathology may not impart as many socially helpful cues to probands. Understanding more about specific sibling characteristics and how they may relate to probands’ social-skill functioning could explain some of the variance in social-domain scores we see among children with ASD.
To investigate the relationship between social-skill functioning among probands with ASD and indices of their siblings’ social competencies and problem behaviors.
Participants were drawn from a larger population of children with ASD who participated in the Simons Simplex Collection (SSC; https://sfari.org/simons-simplex-collection), with a total sample size of 589 pairs of affected children and their designated siblings. Among probands with ASD, 84.3% were male (M age = 8.9 years, SD = 2.9); among siblings, 45.5% were male. The majority of sibling pairs were white (83.2%) and came from families with annual household incomes ranging from $66K—$130K per year (43.9%). Pearson correlations were used to examine relationships between (a) the probands’ reciprocal social interaction (RSI) scores on the Autism Diagnostic Interview-Revised (ADI-R) and social-affect (SA) score on the Autism Diagnostic Observation Schedule (ADOS) and (b) the siblings’ internalizing, externalizing, ADD/ADHD, and total-problem scores on the CBCL, as well as siblings’ scores on the Social Responsiveness Scale (SRS).
Mean scores from the select CBCL subscales were compared to the available normative data (Achenbach, 1991), and no significant differences were found. Significant relationships were noted between proband RSI scores on the ADI-R and sibling CBCL internalizing-problems scores (r = .129, p < .05), ADD/ADHD-problem scores (r = .086, p < .05), and total-problems scores (r = .093, p < .05). Continued analyses include comparable correlations using sibling socialization scores on the Vineland Adaptive Behavior Scales (VABS), as well as linear regression to predict probands’ RSI and SA scores from siblings’ CBCL, SRS, and VABS socialization scores. Proband’s IQ score will be considered as a potentially confounding variable in this analysis.
Preliminary findings suggest a positive, albeit small, relationship between proband social-skill functioning and siblings’ problem behaviors. It is difficult to say the direction of the effect, as the proband’s difficulties could negatively influence sibling outcomes, or the sibling’s competencies could favorably influence the proband’s outcomes. Next-step analyses will explore the degree to which siblings’ scores on the aforementioned measures predict probands’ RSI and SA scores.