Evaluating Differences in Internalizing Behaviors Between Children with ASD and Their Typically-Developing Siblings Across Birth Order and Time

• In Event: Poster Session 10
  In Poster Session: PS 10 Topic - Developmental Disabilities

Abstract

Findings remain mixed as to what extent typically developing (TD) siblings of children with autism spectrum disorder (ASD) are at risk for psychological problems (Tudor et al., 2018). Whereas the literature compares rates of psychological problems in TD siblings to the general population, little research compares such problems in TD siblings to their siblings with ASD. Furthermore, there is continued need for research on how family characteristics, including birth order, may impact psychopathology in TD siblings relative to sibling counterparts.

Participants were 61 caregivers with one child with ASD and at least one TD child categorized into two birth order groups: caregivers who have (1) a first-born TD child and then a child with ASD (First-Born condition); and (2) a first-born child with ASD and then a non-first-born TD child (Non-First-Born condition). Caregivers completed questionnaires measuring internalizing behaviors of the child with ASD and TD sibling (BASC-3) at Time 1 (T1) and two years later at Time 2 (T2).

Independent samples t-tests examined if birth order groups’ internalizing behaviors difference scores (ASDinternalizing –TDinternalizing) varied at T1 and T2 (Table 1). At T1, first-born TD siblings were significantly more concordant to their siblings with ASD in internalizing behaviors (i.e., smaller difference scores) compared to non-first-born TD siblings, indicating first-born TD siblings had higher levels of internalizing behaviors (and more like their sibling with ASD) than non-first-born TD siblings. At T2, first-born TD siblings’ average difference score was negative and, again, was significantly different than that of non-first-born TD siblings.

A moderated multiple regression examining T1 internalizing behaviors difference scores and birth order predicting T2 internalizing behaviors difference scores was significant, F (2,32) = 15.72, p < .001, R2 = .51. When accounting for birth order, T1 difference scores significantly predicted T2 difference scores, ß = .78, p < .001. Birth order was not significant, suggesting birth order does not predict unique change in internalizing behaviors over time. The addition of the interaction term predicted unique variance in T2 difference scores, b = -0.80, SE = 0.32, [95% CI (-1.45, -0.14)]. A post-hoc plot (Figure 1) showed that birth order appears to be more pertinent when a TD sibling’s internalizing behaviors are concordant with the sibling with ASD at T1 (i.e., smaller difference score, higher symptom levels). Specifically, two years later, this concordance in internalizing behaviors seems to be maintained for the non-first-born TD siblings, whereas the first-born TD siblings tend to be discordant on internalizing behaviors relative to their siblings with ASD. Conversely, when a TD sibling’s internalizing behaviors are discordant with the sibling with ASD at T1 (i.e., larger difference, lower symptoms levels), this discordance appears to be maintained two years later, regardless of birth order. In other words, TD first-born siblings with more severe internalizing behaviors tend to improve over time. These findings suggest that being a first-born sibling in a family with a child with autism may serve as a protective factor in the development of internalizing behaviors.

Authors

• Sarah C Boland, Washington State University
  Presenting Author

• Shelby Lee Johnson, Washington State University
  Non-Presenting Author

• Rebecca A Lindsey, Washington State University
  Non-Presenting Author

• Tammy D Barry, Washington State University
  Non-Presenting Author