Autism spectrum disorder (ASD) is a group of severe, life-long developmental disorders. Oxytocin (OT) is a neurohormone involved in both repetitive/rigid and social behaviors. This study is focusing on how a single dose of intranasal OT (IN-OT) affects cognitive rigidity and social perception tasks. Taking OT as a spray through the nose increases social and decreases repetitive behavior in some adults with ASD, and we are exploring if it helps children with ASD similarly. However, it is unclear whether every person with ASD has an abnormal OT level, and if OT affects restrictive or social behavior differently. Consequently, we aim to study whether OT treatment can be effective in treating subgroups with specific features of ASD. We will use approaches utilizing both behavioral and physiological responses to clarify the role of OT in ASD. We will develop a deeper understanding of the range of social and rigid behaviors and use that information to identify persons with ASD who would benefit from OT treatment. Potential subjects will be asked if they want to participate in two sessions in our clinical laboratory where they will get either single dose IN-OT or placebo. After receiving the substance, they will be asked to do a handful of tasks while we monitor heart rate, eye movements, and collect baseline and post intranasal blood, urine and saliva. The levels of hormones, metabolites and peptides related to or interacting with OT will be measures in the collected samples of blood plasma, urine and saliva. Additionally DNA will be extracted from the blood samples to study genes related to OT and ASD.

Inclusion Criteria:

• Participants will be between 5 and 40 years of age.
• All subjects will have a diagnosis of autistic disorder or ASD that was confirmed by administration of the Autism Diagnostic Observation Schedule-WPS (ADOS-WPS) (30).
• Eligible participants must be able to perform the cognitive learning tasks.

Exclusion Criteria:

• Although we acknowledge that concomitant medications, or other types of intervention, may potentially bias study results, participants will be allowed to stay on concomitant medications and non-pharmacologic treatments, provided that no changes are made within 3 months prior to baseline and that no changes are made during the study.
• Individuals that are on antipsychotic drugs will be excluded from participation. All subjects must lack a significant medical history.
• Subjects with any condition, including alcohol and drug abuse, which might interfere with the conduct of the study, confound interpretation of the study results, or endanger their own well-being will be excluded.
• This includes, but is not limited to impairment of renal function, evidence or history of malignancy or any significant hematological, endocrine, respiratory, hepatic, cardiovascular or gastrointestinal disease.
• All female subjects of childbearing capacity will have a urine pregnancy test (a positive test will exclude the subject from participation).
• A pregnancy test will be conducted at both visits prior to drug administration. Uterine contractions may occur in women and are more likely to occur in pregnant women, especially towards the end of pregnancy.
• As a result, we exclude pregnant female patients, sexually active female patients on hormonal birth control and sexually active females who do not use two types of non-hormonal birth control.
• All interested potential subjects will be contacted via phone. If they meet eligibility criteria, two sessions that are approximately two weeks apart and approximately the same time of day will be scheduled. At their first visit, we will review the study and undergo informed consent procedures. Overall study procedures per visit are estimated to take approximately 2-3 hours per session, and are detailed in Table 2.

6 weeks per participant