Exploring Alexithymia, Uncertainty, Anxious Arousal, and Social Anxiety as Mediators of the Relationship Between Sensory Processing Differences and Restricted and Repetitive Behaviors in Autistic Adults

Restricted and repetitive behaviors (RRB) are associated with sensory processing (SP) differences for autistic people, and are thought to be a coping strategy to help manage the sensory environment. Previous work shows that, for autistic people, alexithymia, intolerance of uncertainty (IU), and anxiety mediate the relationship between SP differences and RRB. However, these studies use anxiety measures developed for the general population, and more recent evidence suggests that autistic people may have a different anxiety experience. This study aims to extend previous findings by unpacking the anxiety experience for autistic adults in the relationship between SP differences and RRB, using an autism-specific anxiety measure. Data were available from 426 autistic adults. Serial mediation models tested the relationship between SP differences and RRB, with alexithymia, IU, anxious arousal, and social anxiety as mediators. We identified significant direct effects from SP differences to both repetitive motor behaviors (RMB) and insistence on sameness behaviors (ISB). For RMB, we found indirect effects through anxious arousal, alexithymia-anxious arousal, IU-anxious arousal, and alexithymia-IU-anxious arousal. For ISB, we found indirect effects through IU and alexithymia-IU. Thus, different mechanisms may underpin RMB and ISB. Understanding the anxiety experience of autistic people, alongside the role of SP and RRB, is key to providing tailored support, adjustments, and psychological interventions to autistic people. Future research could benefit from directly investigating the impact of strategies to support SP and anxiety.