Trajectories of Reported Challenging Behaviours Derived from the Aberrant Behavior Checklist in a Cohort of Canadian Children with Autism Spectrum Disorders

Background:  Many children with Autism Spectrum Disorder (ASD) exhibit challenging behaviour that can interfere with child development and family well-being. Hyperactivity and irritability are common components of challenging behaviour. It is important to understand their developmental trajectories from time of diagnosis in order to effectively plan early intervention.

 The Aberrant Behavior Checklist (ABC) was developed to measure the effects of intervention on challenging behaviour for people with intellectual disabilities (Aman, Singh, Stewart, & Field, 1985). The ABC is a 58-item caregiver-rated instrument with five subscales: Irritability, Lethargy, Stereotypy, Hyperactivity and Inappropriate speech, with higher scores indicating more severe problems. It has been used in several intervention studies among children with ASD (Kaat, Lecavalier & Aman, 2014).

Objectives:  Using data from the longitudinal “Pathways in ASD” Study, we aim to examine: (a) the reliability and validity of the ABC in newly diagnosed children, (b) the stability of Hyperactivity and Irritability scores from (i) time of diagnosis at age 2-4 years to age 6 years, and (ii) after the transition to school (from age 6 years to age 12 years), (c) associations with parent- and teacher-reported aggression in participants at age 12.

Methods:  Reliability of the ABC subscales was assessed using Cronbach’s coefficient alpha and validity was assessed using correlations of subscales with the Child Behavior Checklist (CBCL) 1.5-5 and 6-18, Autism Diagnostic Observation Schedule (ADOS) and Vineland Adaptive Behavior Scales-II (VABS-II). Piecewise growth modeling was used to capture the trajectories during the preschool years and the transition at age 6 to and through the school context. Multiple regression was used to examine associations between Irritability and Hyperactivity scores at time of diagnosis with parent- and teacher-rated aggression as rated using the CBCL (controlling for baseline ASD symptoms and gender).

Results:  Baseline data were obtained on 369 children, 84% boys, with mean age 40.8 months (SD 9.1 months). Internal consistencies for the subscales of the ABC varied between Cronbach’s alpha of 0.8 and 0.9. Correlations between the ABC and CBCL subscales were 0.7 or greater, and correlations with the ADOS overall severity metric were low. Wave-to-wave correlations of the ABC Hyperactivity and Irritability subscales were 0.7 or greater. Correlations between the ABC Hyperactivity and Irritability subscales at each wave were 0.5 or greater. Examination of the Hyperactivity subscale trajectory showed relative stability in reported behaviours from time of diagnosis to age 6 years, after which reported Hyperactivity decreased over the school-aged period. However, for the trajectory of the Irritability subscale, a slight but constant decrease was seen from diagnosis to age 12. Parent-reported child Irritability and Hyperactivity scores at time of diagnosis were significantly associated with parent- and teacher-rated aggression problems at age 12.

Conclusions:  The ABC shows adequate reliability and validity in this sample of children with ASD. Different trajectories were observed for Irritability and Hyperactivity subscales. Early childhood irritability and hyperactivity may predict higher levels of aggression at home and school during later childhood. Early intervention planning should explicitly assess child hyperactivity and irritability as important and potentially modifiable targets.