Abstract
BACKGROUND: The severity of tics may influence executive function in children and adolescents diagnosed with tic disorders. The underlying mechanism is still inadequately researched. This study investigates the mediating role of premonitory urges in the relationship between tic severity and executive functioning, alongside the moderating effect of comorbidities. METHODS: A total of 154 children and adolescents, aged 6 to 15 years, diagnosed with tic disorders, were recruited from Fujian, China. The Yale Global Tic Severity Scale (YGTSS), Premonitory Urges for Tics Scale (PUTS), and Behavior Rating Inventory of Executive Function (BRIEF) were utilized to evaluate tic severity, premonitory urges, and executive functioning. R software version 4.4.3 was used for descriptive statistics and Pearson correlation studies. The moderated mediator models were tested using Bayesian Structural Equation Modeling (BSEM). RESULTS: A Bayesian simple mediation model revealed that the premonitory urge fully mediated the association between tic severity and executive functioning. Additionally, comorbidity was found to independently predict both the premonitory urge and executive functioning. In the context of a moderated mediation model, comorbidity intensified the association between tic severity and the premonitory urge, resulting in more pronounced indirect effects on behavioral regulation (BRI) and metacognition (MI). The Index of Moderated Mediation was significant for both BRI and MI, thereby confirming the enhancement of the mediation pathway driven by comorbidity. CONCLUSIONS: This study is the first application of BSEM to clarify the mediating mechanism through which tic severity affects executive functioning via the premonitory urge, while concurrently validating the moderating effect of comorbidities. This finding supports the optimization of clinical assessment and intervention strategies.