Clinical Predictors of Tic-Related Impairment in Children and Adults with Tourette Syndrome

Tic-related impairment drives treatment decisions for Tourette syndrome and related tic disorders. The clinical features most strongly associated with impairment remain unclear.

The aim of this analysis is to identify clinical predictors of tic-related impairment in children and adults with tic disorders in a prospective longitudinal study.

Participants were drawn from the Calgary Tic Registries, undergoing prospective structured assessments. Baseline demographic and psychiatric data, psychotropic medication use, Yale Global Tic Severity Scale (YGTSS) dimension scores, and the number of different tics (NDT) were analyzed. Predictors of impairment were examined using Spearman's correlations, univariate associate screening with false discovery rate correction, least absolute shrinkage and selection operator (LASSO) regression with ordinary least squares refitting, and linear mixed-effects (LME) models to evaluate within-person changes over time.

The sample included 496 participants (848 total assessments). Motor tic interference showed the strongest correlation with impairment (ρ = 0.50), followed by motor tic intensity and frequency. The NDTs correlated with impairment more strongly than most individual YGTSS dimensions. In LASSO regression, seven predictors remained significant: motor tic interference, frequency and complexity, phonic tic interference, older age, female sex, and absence of autism. The LME models analyzed data from all participants with at least one follow-up visit. LME models showed that increases in total tic score predicted higher impairment and that impairment decreased modestly over time.

Motor tic interference is the most robust predictor of tic-related impairment. Older age and female sex further contribute to functional burden. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.