Additional Study Information: The Translational Medicine Program at the Center for Autism and the Developing Brain is recruiting individuals with autism from 5 -17 years of age with an IQ over 70 to participate in our study called aV1ation. The purpose of this study is to test an investigational medicine that blocks a hormone receptor in the brain linked to the control of socialization, stress, anxiety and aggression. We want to see if this medicine is effective as a treatment to help improve social functioning in children with ASD. To determine this, participants will be randomly assigned to take the investigational drug or a placebo pill. Participation lasts up to 39 weeks and will involve regular visits to the Center for Autism and the Developing Brain. This will allow the study team to assess participants general health, social communication skills and social interaction skills. At the end of the 24 weeks, participants have the option to enter a 1-year extension, during which everyone will receive the investigational drug (even those who previously received a placebo). Participants will not have to pay for any study related treatments, lab tests, or assessments and will also be reimbursed $50 per visit.