Internalizing and Externalizing Problems in Children with ASD, ADHD, and OCD: Identifying Behavioural Profiles Within and Across Diagnostic Categories

Abstract

Background: Emerging evidence suggests that there is both within-disorder heterogeneity and across-disorder overlap in the clinical presentation of children with ASD, ADHD, and OCD. Two prevalent dimensional phenotypes in children with these NDDs that warrant close attention, and are suitable for cross-disorder investigation, are internalizing and externalizing problems. Objectives: The current study uses a data-driven, diagnosis-agnostic approach to identify homogenous clusters that describe behavioural profiles of internalizing and externalizing problems within and across ASD, ADHD, and OCD. Methods: Data on 1565 children (M = 10.76 years) were drawn from the Province of Ontario Neurodevelopmental Disorder (POND) Network. Non-hierarchical clustering approaches were used to empirically derive, distinct behavioural profiles of internalizing and externalizing problems indexed by the Child Behavior Checklist (CBCL). Empirically derived groups were characterized using measures of adaptive functioning indexed by the Adaptive Behaviour Assessment (ABAS-II), and interpreted in relation to original diagnoses. Results: Cluster analyses identified four distinct behavioural profiles that cut across all diagnostic groups: High Internalizing Externalizing (HIE; 15%), High Externalizing (HE; 21%), Low Internalizing Externalizing (LIE; 38%), and Low Externalizing (LE; 26%). Derived clusters had variable levels of adaptive behaviours and reflected different behavioural profiles than the ones defined by the original diagnostic category groups of ASD, ADHD, and OCD. Conclusion: Data-driven, diagnosis-agnostic approaches can inform our understanding of the between and within phenotypic heterogeneity seen in ASD, ADHD, and OCD. Empirical ways of classifying children with homogeneous behavioural profiles may complement existing diagnostic models in our efforts to develop cross-disorder, more personalized interventions for children with neurodevelopmental disorders.