Buspirone Treatment of Anxiety in Williams Syndrome

Inclusion Criteria: 1. Age 5 to 65 years of age. 2. Diagnosis of WS confirmed via genetic testing or a clinical diagnosis made by a clinician with significant experience treating patients with WS. 3. Clinically significant anxiety as evidenced by a Pediatric Anxiety Rating Scale (PARS) score of 10 or greater (5-item scale). The PARS ("The Pediatric Anxiety Rating Scale (PARS): Development and psychometric properties." 2002) was chosen as an inclusion criterion (and outcome measure) since it assesses severity across common anxiety disorders in children including generalized anxiety, social anxiety, separation anxiety, and transition-associated anxiety. In addition, it is an instrument that allows the clinician to incorporate both child and parent report into a final clinician-rated score for each item. 4. A Clinical Global Impression Severity Item score ≥ 4 (moderate) for anxiety symptoms at Screen and Baseline. Exclusion Criteria: 1. Diagnosis of OCD, posttraumatic stress disorder, major mood disorder, psychotic disorder, or substance use disorder. These disorders are exclusionary since the primary treatment of these disorders may require acute psychosocial treatments or other medications that would confound the assessments. 2. Presence of any past or present conditions that would make treatment with buspirone unsafe. This includes allergy to buspirone, liver or kidney disease, and pregnancy (or being sexually active without using acceptable methods to prevent pregnancy). 3. Use of selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), benzodiazepines, antihistamines (as needed use of an antihistamine for the treatment of allergies will be permitted), or antipsychotics. Subjects will need to be off medications from these classes for at least 5 elimination half-lives prior to beginning the trial. 4. Use of other psychotropic medications which are ineffective, poorly tolerated, or sub-optimal in terms of dose. A board-certified child and adolescent psychiatrist will assess any other psychotropic medications being used and determine whether they are effective, tolerated, and optimal in terms of dose. Concurrent use of a psychotropic medication (other than SSRIs, SNRIs, benzodiazepines, antihistamines, or antipsychotics) will be allowed if the dose has been stable for 30 days and if they meet the criteria of effectiveness, tolerability, and dose. 5. Previous adequate trial of buspirone. An adequate trial will be defined as a total daily dose of ≥20 mg for at least 4 weeks. In addition, subjects who developed significant adverse effects during a trial of buspirone at any dose or duration will be excluded. 6. Severe or profound intellectual disability based on clinical assessment and review of standardized assessment of cognitive skills. Subjects will undergo standardized testing and be evaluated by study staff to determine cognitive capabilities. Participants determined to have severe or profound intellectual disability will be excluded.