Making Sense of Repetitive Behaviours in Autism Spectrum Disorder: The Relevance of Intolerance of Uncertainty

Background: Restricted and repetitive behaviours (RRB) are a hallmark feature of Autism Spectrum Disorder (ASD), although a clear understanding of the relationship between RRB and other features  of ASD is yet to be developed. Difficulties managing sensory input and the presence of anxiety have both been associated with higher levels of RRB in young children with ASD (Chen, Rodgers & McConachie 2009; Rodgers, et al., 2012). The mechanism via which these two constructs may contribute to the presence of RRB has not been fully explored. The construct of intolerance of uncertainty (IU; Dugas et al., 1998) is used here to attempt to bridge this divide. Intolerance of uncertainty is an assumption that uncertainty is stressful and upsetting and unexpected events are negative and should be avoided at all costs. It is hypothesised that intolerance of uncertainty may make a significant contribution to the relationship between sensory sensitivities anxiety and RRB in ASD.

Objectives: To examine the contribution of sensory sensitivities, anxiety and intolerance of uncertainty to the presence of RRB.

Methods: Parents of 23 young people with a diagnosis of ASD, aged between 8-15 years,  completed the Spence Children’s Anxiety Scale – Parent version (SCAS-P); the Intolerance of Uncertainty Scale Parent version (IUS-P); the Repetitive Behaviour Questionnaire (RBQ) and the Short Sensory Profile (SSP).

Results: Total RBQ score correlated with total SSP score (r= -.39, p=.021), total SCAS-P score (r=.52, p=.005) and total IUS-P score (r=.61, p=.001).

To explore the relationship between sensory sensitivities, anxiety and IU in predicting RRB a hierarchical regression model was built. SSP total score entered at Step 1 was marginally significant in predicting RRB (β = --.15, p = .06), when total SCAS-P score was entered at Step 2 it was a significant predictor of RRB (β = .27, p = .02), whilst the contribution of sensory sensitivities was reduced (β = --.10, p = .15). IUS-P total score entered at Step 3 further reduced the contribution of both sensory sensitivities (β = --.09, p = .15) and anxiety (β = .15, p = .17), whilst IU was found to be was a significant predictor of RRB (β = .37, p= .02).

Conclusions: Findings reveal that intolerance of uncertainty may play an important mediating role in the previously reported relationship between sensory sensitivities, RRB and anxiety in children with ASD. Sensory abnormalities present a myriad of challenges for the young person with ASD. Facing such difficulties on a day to day basis may contribute to the development of anxiety which is characterised by intolerance of uncertainty and ultimately circumscribed interests, insistence on sameness, rituals and routines in an attempt to avoid aversive sensory experiences and reduce demand. Recent developments in cognitive behavioural therapy approaches addressing intolerance of uncertainty may hold promise for reducing RRB and anxiety in young people with ASD.