Study of Glutathione, Vitamin C and Cysteine in Children With Autism and Severe Behavior Problems

Inclusion Criteria: * Age 5 to 16 years, inclusive * Diagnosed with autism using the ADI-R (Autism Diagnostic Interview-Revised) * ABC Irritability/Agitation subscale score (Aberrant Behavior Checklist Subscale) ≥ 18 * CGI-S score (Clinical Global Impression-Severity Scale) ≥ 4 * Must be drug naïve or on a stable dose of medication(s) and educational/behavioral interventions for one month prior to participation * Parent/legal guardian must provide written consent and required research authorization (i.e. HIPAA) prior to the performance of any study procedures. Exclusion Criteria: * Presence of another disorder on the autism spectrum including PDD-NOS (Pervasive Developmental Disorder Not Otherwise Specified), Asperger's, and Rett's Syndrome * Patient with a known cause of autism such as Fragile X * Evidence of significant renal dysfunction (e.g. GFR estimated by the Schwartz formula \< 50 mL/min or serum creatinine \> 2.5 X upper limit of normal for age) * Evidence of significant hepatic dysfunction (serum transaminases \> 2.5 X the upper limit of normal) * Known hypersensitivity to glutathione, vitamin C or NAC * Pregnant or lactating female * Inability of subject and parent to be able to comply with requirements for study visits and procedures * Presence of major mental illness * History of antioxidant supplementation.