Differential associations between features of autism and internalizing and externalizing behaviours: a transdiagnostic approach

While many autistic children have high levels of internalizing or externalizing behaviours, research seldom examines whether these behaviours are differentially associated with key features of autism. The current study used a transdiagnostic approach to characterize the inter-relationship between restricted and repetitive behaviours (RRBs) and social communication autistic features, and internalizing and externalizing behaviours.

Method: The study included 136 6-7 year-olds with school-identified emotional and behavioural difficulties. Parents reported on their child’s current repetitive behaviour using The Repetitive Behaviour Questionnaire-2 (Leekam et al., 2007) and their difficulties with pragmatic language social communication using the Revised Children’s Communication Checklist (Wellnitz et al., 2021). Internalizing and externalizing were measured using The Strengths and Difficulties Questionnaire (Goodman et al., 1997). Regression analyses examined differential and relative contributions made by RRBs and pragmatic language to internalizing and externalizing behaviours.

Results: RRBs, and particularly the insistence on sameness subdomain, made a stronger contribution than pragmatic language in the regression model for internalizing behaviours. For externalizing behaviours, the opposite was true; pragmatic language made a stronger contribution than RRBs. RRBs – specifically repetitive sensory and motor behaviours subdomain – only made a significant contribution to externalizing when entered before pragmatic language.

Discussion: By characterising the inter-relationship between autistic features and internalising and externalizing behaviours beyond traditional, categorically defined diagnostic boundaries, these results clarify potential target areas for supporting children with emotional and behavioural difficulties. For example, externalising behaviours might benefit from support for pragmatic language while difficulty with change in routine might benefit from emotion-related support.