Targeting the Neurobiology of RRB in Autism Using N-acetylcysteine: Trial

Inclusion Criteria: * children between 3 years and 12 years 11 months * diagnosis of autism spectrum disorder confirmed with the Autism Diagnostic Interview- Revised and the Autism Diagnostic Observation Schedule-2, Brief Observation of Symptoms of Autism, or Childhood Autism Rating Scale * at least moderate severity of restricted and repetitive behaviors defined by a Children's Yale-Brown Obsessive Compulsive Scale for Autism Spectrum Disorder score ≥ 11 * physical development indicative of prepubescence as defined by criteria for Tanner Stage 1 * if home address is within 300 miles of the primary study site, participants must pass MR safety screening (e.g., no metal in the body) and attempt baseline neuroimaging (MRI or EEG), otherwise baseline neuroimaging is not required for participation * have stable medication regimens (≥ 30 days) and psychosocial treatments (≥ 60 days) prior to randomization with no anticipated changes during the trial Exclusion Criteria: * presence of known genetic abnormalities associated with ASD (e.g. Fragile X) * current or life-time diagnosis of severe psychiatric disorder (e.g., schizophrenia) * presence of significant medical problems * the inability of at least one caregiver to speak and read English to a sufficient level * participants taking glutathione agents/prodrugs * history of any adverse effects to glutathione agents/prodrugs * the inability to drink a sample study compound dissolved in liquid