Exploring the Relationship Between Autism Symptoms, Language Ability, and Externalizing Behaviors in Children with Autism
Individuals with autism spectrum disorders (ASD) often possess ADHD symptoms and problematic externalizing behaviors, which can exacerbate autism symptoms and reduce adaptive functioning skills (Sikora, Vora, Coury & Rosenberg, 2012). However, the relationship between these ADHD symptoms/externalizing behaviors and autism in children with minimal language has yet to be established.
The present study aimed to (1) evaluate the differences in presentation of externalizing behaviors between individuals with fewer than 5 words compared to those with more than 5 words and (2) to determine the relationship between autism characteristics and externalizing behaviors controlling for demographic characteristics.
The present study included cross-sectional participant data from the Simons Simplex Collection and the National Database of Autism Research. Individuals who had received an ADOS Module 1 assessment were included in the presented analyses (Lord et al., 2012). Those who were rated as having fewer than 5 words on the ADOS item Overall Level of Non-Echoed Spoken Language were included in the “no words” group (N= 354) and individuals with more than 5 words were included in the “some words” group (N= 538). Externalizing behaviors were measured using the Child Behavior Checklist (CBCL) 1.5-5 or 6-18 Aggressive Behavior and Attention Problems and the Aberrant Behavior Checklist (ABC) Hyperactivity and Irritability subscales. First, magnitudes of mean differences between language groups on externalizing behaviors were computed using t-tests. Second, ADOS subdomains, gender, age, and language level ("no words", "some words"), were evaluated as predictors of externalizing behaviors in four separate regression models and insignificant predictors were excluded in the presented analyses. A Bonferroni correction (p<.0125) was applied to correct for multiple comparisons.
Language level did not significantly predict externalizing behaviors (Attention Problems: β=0.10, p=.99, Aggressive Behavior: β=0.33, p=.80, Hyperactivity: β=0.31, p=.09, Irritability: β=0.43, p=.17). None of the included variables were significant predictors of Aggressive Behavior F(12,452)=1.51, p=.12. ADOS RRB uniquely predicted both Attention Problems F(1,466)=12.71, p<.01 and Irritability F(1,504)=7.92, p<.01 such that more severe RRBs were associated with greater attention problems (β=0.16) and irritability (β=0.12). In contrast, Hyperactivity was predicted by ADOS SA (p<.01) and age (F(2,695)=18.77, (p <.01), such that more severe social affect was associated with higher levels of hyperactivity (β=0.14), and increasing age was associated with fewer symptoms of hyperactivity (β=-0.18).
While presence of externalizing behaviors do not differ significantly for autistic individuals with no words compared to some language, externalizing behavior domains show varying association with social affect and RRBs. Individuals with more impaired social affect display more symptoms of hyperactivity, suggesting that treatment of hyperactivity symptoms may improve level of social engagement. It is noteworthy that the severity of RRBs is only associated with higher irritability and more attention problems. Determining the nature and directionality of the relationship between RRBs and attention and irritability is an important question for future research as well as exploration of additional predictors of externalizing behavior in minimally verbal individuals with autism to potentially facilitate intervention for core deficits.