Comorbidities and Adaptive Behavior Using the Behavior Assessment System for Children – Version 3 in Children with Autism Spectrum Disorder: Results from the ABC-CT Feasibility Study

Background: Approximately 70% of children with autism spectrum disorder (ASD) develop comorbid psychiatric conditions that contribute to greater functional impairment (Simonoff et al., 2008). Despite the high prevalence of psychiatric comorbidities, they are inherently difficult to diagnose in children with ASD, and valid and reliable measures are needed (Lecavalier et al., 2014). Broad-based parent report measures, such as the Behavior Assessment System for Children-Version 3 (BASC-3), can be useful for identifying co-occurring conditions and related functional impairment.

Objectives: This study investigated group differences in psychiatric symptoms and adaptive functioning in children with ASD and typically developing children. In addition, it examined convergent validity of the BASC-3 in children with ASD and explored the relation between psychiatric symptoms and greater adaptive impairment.

Methods: As part of the Autism Biomarker Consortium for Clinical Trials (ABC-CT) feasibility study, we examined psychiatric symptoms and adaptive behavior in participants with ASD (n=23) and typically developing controls (n=26), ages 4-11 years, with IQ>50. Caregivers completed the BASC-3, the Child & Adolescent Symptom Inventory-5 (CASI-5)/Early Childhood Inventory-5 (ECI-5) parent questionnaires and the Vineland Adaptive Behavior Scales, Second Edition (VABS-II) interview. ASD diagnosis was confirmed using the Autism Diagnositc Observation Schedule-2 (Lord et al., 2012) and the Autism Diagnositic Interview-Revised (Rutter, LeCouteur & Lord, 2003).

Results: Results from independent sample t-tests, revealed children with ASD had significantly higher standard scores on the BASC-3 Externalizing Problems Composite (t(30.834)=-5.567, p<.001), Internalizing Problems Composite (t(47)=-3.775, p<.001), and the Adaptive Skills Composite (t(47)=10.558, p<.001) than typically developing children.

The BASC-3 scale scores converged with the VABS-II domain scores with the exception of the socialization domain. The BASC-3 Activities of Daily Living scale correlated with the VABS-II Daily Living Skills domain, (r=.677, p<.001). The BASC-3 Functional Communication scale correlated with the VABS-II Communication domain (r=.580, p=.004). The BASC-3 Social Skills scale did not correlate with the VABS-II Socialization domain (r=.308, p=.152).

Furthermore, Pearson correlations indicated convergence of BASC-3 clinical symptom scales and CASI-5/ECI-5 scales. The BASC-3 Hyperactivity scale correlated with the CASI-5/ECI-5 Hyperactive-Impulsive scale (r=.798, p<.001). The BASC-3 Attention Problems scale correlated with the CASI-5/ECI-5 Inattentive scale (r=.431, p=.045). The BASC-3 Anxiety scale correlated with the CASI-5/ECI-5 Generalized Anxiety scale (r=.878, p<.001). The BASC-3 Depression scale correlated with CASI-5/ECI-5 Dysthymic scale (r=.767, p<.001).

The BASC-3 Internalizing Problems Composite negatively correlated with the BASC-3 Adaptive Skills Composite (r=-.416, p=.048). There was not a significant correlation between the Externalizing Problems Composite and the Adaptive Skills Composite (r=-.1, p=.65).

Conclusions: Findings indicate the BASC-3 demonstrates adequate convergent validity with more targeted, commonly used measures of psychiatric comorbidity (CASI-5/ECI-5) and adaptive functioning (VABS-II) in ASD. This study contributes to the growing literature on accurate assessment in ASD and suggests the BASC-3 may be a useful broad-based parent report measure for identifying psychiatric conditions and adaptive impairment in children with ASD. Furthermore, findings on the relation between greater internalizing problems and poorer adaptive functioning skills may inform intervention research, as adaptive functioning skills may be an important focus of treatment in children with ASD and co-occurring internalizing symptomatology.