A Randomized, Controlled Trial of Intranasal Oxytocin as an Adjunct to Behavioral Therapy for Autism Spectrum Disorder

Inclusion Criteria: * Age 18-40 * Able to attend in person therapy sessions in Boston * Male * English-speaking * Normal or corrected vision * No history of known genetic disorder, significant motor developmental difficulties, prematurity or brain injury * IQ \> 90, as determined by the WASI * Score above the cutoff on the Reciprocal Social Interactions and the Restricted, Repetitive, and Stereotyped Behaviors Domains on the ADI-R, meet criteria for PDD or autism on the ADOS, and/or meet DSM-IV criteria for Autism Spectrum Disorder according to clinician interview. Exclusion Criteria: * Current use of certain endocrinologically relevant medications * Current dependence on substances other than tobacco or caffeine * History of serious medical illness, including neurological, endocrine, cardiac, respiratory, and metabolic diseases that are counter-indications to oxytocin * Severe, current psychiatric disorder (ie, current mania, severe depression, psychosis, suicidality, severe aggression) * Long QT, as determined by baseline EKG * Current participation in other psychotherapy Additional exclusion criteria for MRI scan only: Participants who are MRI-ineligible will be enrolled in the clinical trial portion of the study, but will not undergo the MRI scan at MIT. Exclusion criteria for MRI are: * Presence of metal implants or other metal in the body * History of claustrophobia or inability to tolerate MRI