Feasibility, reproducibility, and clinical validity of the pediatric anxiety rating scale-revised for fragile X syndrome.

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and the most common known genetic cause of autism. FXS is associated with psychiatric impairments, including anxiety disorders. There is a paucity of well-developed measures to characterize anxiety in FXS. However, such scales are needed to measure therapeutic responses to interventions. The Pediatric Anxiety Rating Scale-Revised (PARS-R) was evaluated in 49 individuals with FXS. Feasibility, reproducibility, and clinical validity were assessed. High inter-rater, test-retest, and cross-site reliability were achieved. PARS-R scores were correlated with parent-report and physician ratings of anxiety, suggesting good clinical validity. Results were similar within gender and age subgroups. The PARS-R is a promising tool for measuring the efficacy of interventions targeting anxiety in FXS.