Background: Self-injurious behaviours (SIB) occur at a high rate in autistic children with a co-occurring intellectual disability (ID). Delineating the individual characteristics which contribute to the observed differences in SIB emergence and outcomes will extend the operant model and inform proactive intervention strategies. The present study extended prior work, which has identified a role for reduced behavioural inhibition, through the direct measurement of executive function (EF) abilities in this population.

Method: A developmentally-appropriate EF battery was administered remotely to 60 autistic children with ID (mean age = 10.22, range 5-15, 70% SIB, 14 girls). Questionnaire data on SIB, EF, and adaptive behaviour were collected. Analyses evaluated the relationship between the EF outcome measures and SIB, as well as the unique contribution of EF to the presence and severity of SIB.

Results: SIB was moderately associated with a direct measure of updating and inhibition (r = – .28, p