Association Between Anticholinergic Burden and Repetitive Behavior Subtypes in Children and Adolescents with Autism Spectrum Disorder

Background: Repetitive behaviors constitute a core feature of autism spectrum disorder (ASD) and represent a heterogeneous group of behavioral patterns involving different neurocognitive mechanisms. The cholinergic system plays an important modulatory role in attention, cognitive flexibility, and behavioral control. However, the potential relationship between anticholinergic burden and different subtypes of repetitive behaviors in adolescents with ASD has not been systematically investigated. Methods: This cross-sectional study included adolescents aged 8–17 years diagnosed with ASD according to DSM-5 criteria. Participants were grouped according to their anticholinergic burden (ACB) scores. Repetitive behaviors were assessed using the Repetitive Behavior Scale-Revised (RBS-R). Behavioral problems were evaluated with the Nisonger Child Behavior Rating Form (NCBRF) and the Aberrant Behavior Checklist (ABC). Group comparisons, covariance analyses, partial correlations, and regression analyses were conducted to examine the relationship between anticholinergic burden and behavioral outcomes. Results: Participants with clinically significant anticholinergic burden demonstrated higher scores on ritualistic behaviors and insistence on sameness compared with those with low or absent anticholinergic burden. These associations remained significant after controlling for demographic variables. In contrast, no significant relationships were observed between anticholinergic burden and stereotyped behaviors, compulsive behaviors, or restricted interests. Correlation and regression analyses yielded consistent findings, indicating that higher anticholinergic burden was associated with increased severity of ritualistic behavior patterns. Conclusions: The findings suggest that anticholinergic burden may be differentially associated with specific subtypes of repetitive behaviors in adolescents with ASD, particularly ritualistic behaviors and insistence on sameness. These results highlight the potential relevance of cholinergic mechanisms in behavioral regulation and cognitive flexibility in ASD. Further longitudinal studies are needed to clarify the direction and clinical implications of these associations.