Abstract
Autistic children experience higher rates of anxiety compared to their nonautistic peers; however, psychotherapeutic treatments for anxiety such as cognitive behavioral therapy often have limited effectiveness in this population. This study protocol presents a novel, co-designed video-recorded yoga intervention for anxiety, tailored to the unique needs of autistic children. The proposed randomized controlled trial aims to evaluate the efficacy of this intervention compared to a treatment-as-usual waitlist control group. Primary outcomes include changes in anxiety severity, assessed using the Anxiety Disorders Interview Schedule or DSM-5 (ADIS-5) and the Anxiety Scale for Children with Autism Spectrum Disorder (ASC-ASD). Secondary outcomes examine emotion regulation and intolerance of uncertainty using the Emotion Dysregulation Inventory (EDI) and the Intolerance of Uncertainty Scale Child version (IUSC), alongside physiological changes in heart rate variability. Data will be analyzed using repeated measures analysis to assess intervention effects, with mediation analysis exploring the roles of emotion regulation, intolerance of uncertainty, and autonomic function in anxiety reduction. Findings will contribute to the growing evidence base for complementary interventions in autistic populations. If effective, this co-designed yoga intervention could provide an accessible, adaptable, and scalable option for treating anxiety in autistic children, particularly those facing barriers to traditional therapies.