Anxiety and repetitive behaviours in autism spectrum disorders and williams syndrome: a cross-syndrome comparison.

Rodgers et al. (2012) compared two groups of children: kids with autism and kids with Williams syndrome. They asked parents to fill out checklists about anxiety and repetitive behaviors. The goal was to see if more repetitive behaviors went hand-in-hand with higher anxiety in each group.

Children with autism showed higher anxiety than children with Williams syndrome. Within the autism group, kids who had more repetitive behaviors also had more anxiety. That link did not show up in the Williams group.

Soto et al. (2024) and Aponte et al. (2025) found the same anxiety-repetitive-behavior link in autistic youth and adults. Their results extend the 2012 finding to new ages and to non-speaking youth with ID.

Storch et al. (2012) zoomed in on one type of repetitive behavior—acting out special interests in play—and also tied it to anxiety. This conceptual replication shows the link holds even when you measure the behavior differently.

Taylor et al. (2017) seems to disagree. They saw that baseline repetitive behaviors only predicted later anxiety until they controlled for baseline anxiety. After that, the link vanished. The clash is mostly about timing: Jacqui et al. looked at one time point, while J et al. tracked kids over a year and found anxiety itself is the stronger predictor.

If you see a spike in hand-flapping, lining up toys, or scripted talk, treat it as a red flag for anxiety. Screen for anxiety right away and add coping skills to the behavior plan. Targeting both areas together may give you faster gains than treating either one alone.