Short report: Relationships between sensory processing, repetitive behaviors, anxiety, and intolerance of uncertainty in autism spectrum disorder and Williams syndrome.
Uncertainty drives repetitive behaviors in Williams syndrome, not in autism—tailor your intervention to the diagnosis.
01Research in Context
What this study did
Król et al. (2019) asked parents to fill out four short checklists. The checklists measured sensory issues, repetitive behaviors, anxiety, and intolerance of uncertainty.
They collected answers from families of children with autism and children with Williams syndrome. Then they used statistics to see which feelings link sensory problems to repetitive behaviors in each group.
What they found
In autism, sensory issues connected straight to repetitive behaviors. Intolerance of uncertainty did not change this link.
In Williams syndrome, the story was different. Intolerance of uncertainty fully explained why sensory issues led to more repetitive behaviors. When uncertainty was held constant, the direct path disappeared.
How this fits with other research
Richards et al. (2017) also saw a tight anxiety–repetitive-behavior tie in autism. Their youth self-reports match the autism half of the new study, showing the link is reliable.
Spackman et al. (2025) widened the lens to ADHD and OCD. They found anxiety predicts insistence on sameness across all diagnoses, echoing the autism result but showing the pattern is not autism-specific.
Uljarević et al. (2017) looked at fear instead of uncertainty. Fear tracked with repetitive behaviors in autism and Down syndrome, yet the effect was strongest in autism, lining up with the new direct path found there.
Why it matters
If you treat a child with Williams syndrome, reduce uncertainty first. Visual schedules, warnings before change, or priming can soften the urge to engage in repetitive behaviors. For autistic kids, sensory supports remain key, but you can worry less about uncertainty training. One quick move: add a five-minute warning before transitions for Williams syndrome clients this week and watch repetitive behaviors drop.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Give advance notice before schedule changes for kids with Williams syndrome.
02At a glance
03Original abstract
Autism spectrum disorder (ASD) and Williams syndrome (WS) share psychopathology relating to sensory processing and repetitive behaviors. The relationships between the sensory features and repetitive behaviors in both disorders, and the mechanisms underlying these relationships are not well understood. The aim of this study was to examine the relationships between sensory processing, repetitive behaviors, anxiety, and intolerance of uncertainty in children with ASD and those with WS to better understand the complexity of psychopathology in these disorders. Parents of 19 children with ASD and 16 children with WS, aged between 4 and 9 years, were asked to complete questionnaires assessing their children's sensory experiences, anxiety symptoms, severity and frequency of repetitive behaviors, and level of intolerance of uncertainty. Serial mediation analysis was performed. Direct significant relationships between sensory features and repetitive behaviors were found only for the ASD group. The relationship between sensory processing difficulties and repetitive behaviors was mediated via intolerance of uncertainty in WS. The findings support the value of considering the complexity of the mechanisms underlying the relationship between sensory processing and repetitive behaviors across neurodevelopmental disorders and the mechanisms underlying these aspects of psychopathology in these groups. Understanding these relationships will shed light on some of the most challenging and intractable characteristics of both conditions and inform suitable interventions to improve quality of life for individuals with either ASD or WS. Autism Research 2019, 12: 759-765. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: In autism spectrum disorder (ASD) and Williams syndrome (WS) difficulties processing the sensory aspects of the environment, repetitive behaviors and high levels of anxiety co-occur, but the relationships between these features are not well understood. This study found that sensory difficulties were directly associated with repetitive behaviors in children with ASD, but not WS, and in WS this relationship was mediated by intolerance of uncertainty. The findings support the value of considering the complexity of the mechanisms underlying the relationship between sensory processing and repetitive behaviors across neurodevelopmental disorders.
Autism research : official journal of the International Society for Autism Research, 2019 · doi:10.1002/aur.2096