A Prospective Open-Label Trial of Buspirone for the Treatment of Anxiety in Williams Syndrome.

Study Design: Prospective open-label trial. Objectives: The objective of this study was to determine whether buspirone showed preliminary evidence of effectiveness, safety, and tolerability in individuals with Williams syndrome (WS). Methods: This is a 16-week, prospective, flexibly dosed, open-label trial of buspirone in 20 individuals with WS aged 5-65 years. The primary outcome measure was the Pediatric Anxiety Rating Scale (PARS). Results: Buspirone use (mean dose, 22.6 mg per day) was associated with a reduction in anxiety severity, with Cohen's d estimate of -4.02 for the PARS. All 18 participants who completed the study received the Clinical Global Impression-Improvement subscale score for anxiety of "much improved" or "very much improved." No serious or severe adverse events occurred during the trial, and no participants discontinued the study due to adverse events. Conclusion: Buspirone was safe and well tolerated. It was also associated with a reduction in anxiety severity. Given these findings, a double-blind, placebo-controlled study of buspirone in WS is warranted.