The prevalence of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) is increasing, with a tendency for co-occurrence. Some studies indicate a connection between atypical sensory processing and executive function. This study aims to explore the distinctive etiology of executive function deficits in children with ASD+ADHD by investigating the relationship between sensory processing and executive function, comparing children with ASD, ASD+ADHD, ADHD, and typically developing children (TD). Method: Sensory Profile 2 (SP-2) and Behavior Rating Inventory of Executive Function 2 (BRIEF-2) were measured in 120 school-aged children. The results of the above scales were compared across these four groups, and correlation and regression analyses between BRIEF2 and SP2 were conducted. Results: Our research revealed varying levels of atypical sensory processing and executive function anomalies across the three neurodevelopmental disorder groups compared to the TD group. The ASD+ADHD group showed particularly significant differences. The heightened emotional problems observed in ASD+ADHD children may be associated with more prominent atypical sensory processing. Variance analysis of inhibitory function revealed differences between ASD+ADHD and ADHD children, suggesting distinct etiological mechanisms for attention issues between ASD+ADHD and ADHD. Conclusions: ASD+ADHD represents a phenotype distinct from both ASD and ADHD. Special consideration should be given to interventions for children with ASD+ADHD. The results of this study may offer a new perspective on understanding the occurrence of ASD+ADHD and potential individualized intervention methods.

Background: Individuals with autism spectrum disorder (ASD) commonly display challenges in social interaction, executive functioning, and sensory processing. Nevertheless, the interrelationships among these domains are not yet fully understood. This study aimed to elucidate whether sensory processing affects social functioning in children with ASD through the mediating role of executive functioning. Methods: A total of 88 children and adolescents with ASD, aged 7 to 14 years, were enrolled. Parent-reported measures included the social responsiveness scale (SRS; social functioning), the behavior rating inventory of executive function–second edition (BRIEF-2; executive functioning), and the sensory profile–second edition (SP-2; sensory processing). Mediation analysis was conducted to examine the proposed relationships. Results: The results indicated that emotional regulation, a component of executive functioning, fully mediated the relationship between sensory avoiding and social responsiveness, whereas it partially mediated the relationship between sensory registration and social responsiveness. Additionally, behavioral regulation, another dimension of executive functioning, partially mediated the effects of both sensory avoiding and sensory registration on social responsiveness. These relationships remained significant after controlling for gender, age, and intelligence. Conclusion: These findings underscore the importance of both sensory processing and executive functioning in the social responsiveness of children with ASD. The results suggest a potential mechanistic framework in which executive functions serve as a mediating factor between sensory processing and social behavior in this population.