This study was withdrawn due to competing research interests and slow recruitment.

The main objective of this exploratory 8-week pilot study is to evaluate the safety and efficacy of buspirone for the treatment of anxiety in youth (ages 6-17 years) with autism spectrum disorders. The study results will be used to generate hypotheses for a larger randomized-controlled trial with explicit hypotheses and sufficient statistical power.

Inclusion Criteria:

• Male or female participants between 6 and 17 years of age
• DSM-5 ASD diagnostic criteria as established by clinical diagnostic interview
• Participants with a score of ≥60 or more on the Anxiety/Depression subscale of CBCL
• Subjects can be taking psychotropic medications if they have been on the medication for at least 4 weeks prior to initiating study treatment and if they are on a stable dose, provided the medication is not listed in the Concomitant Medications section of the protocol.

Exclusion Criteria:

• History of active seizure disorder (EEG suggestive of seizure activity and/or history of seizure in last 1 month)
• Subjects with a medical condition or treatment that will either jeopardize subject safety or affect the scientific merit of the study, including:
• Pregnant or nursing females
• Organic brain disorders
• Uncorrected hypothyroidism or hyperthyroidism
• Clinically significant abnormalities on ECG (e.g., QT prolongation, arrhythmia)
• History of renal or hepatic impairment.
• Clinically unstable psychiatric conditions or judged to be at serious suicidal risk
• Current diagnosis of schizophrenia or bipolar disorder
• History of substance use (except nicotine or caffeine) within past 3 months or urine drug screen positive for substances of abuse
• Current treatment with medication with primary central nervous system activity (as specified in the Concomitant Medication section of the protocol)
• A non-responder or history of intolerance to buspirone, after treatment at an adequate dose and duration as determined by the clinician
• Subjects currently taking monoamine oxidase inhibitors (MAOI) and/or CYP3A4 inducers or inhibitors including nefazodone, diltiazem, verapamil, erythromaycin, itraconazole, or rifampin.