Autism is a pervasive developmental disorder characterized by core deficits in social behavior and communication and the presence of repetitive/stereotyped behaviors. The objective of the study is to evaluate the efficacy of Esomeprazole as a treatment for social communication deficits in children with Autism Spectrum Disorder (ASD). This prospective 12 week open-label study will invite 25 children with ASD between the ages of 2 and 6 years of age to participate.

Inclusion Criteria:

• outpatients 2 to 6 years of age;
• males and females who are physically healthy;
• diagnosis of autism spectrum disorder based on clinical evaluation and DSM-5 criteria, and confirmed using the Autism Diagnostic Interview-Revised, and the Autism Diagnostic Observation Schedule or Childhood Autism Rating Scale second edition (CARS-2)
• care provider who could reliably bring subject to clinic visits, could provide trustworthy ratings, and interacted with subject on a regular basis;
• ability of subject to swallow the compound;
• stable concomitant medications for at least 2 weeks (4 weeks if patient took fluoxetine);
• no planned changes in psychosocial interventions during the open-label trial.

Exclusion Criteria:

• DSM-5 diagnosis of schizophrenia, schizoaffective disorder, or psychotic disorder not otherwise specified;
• prior adequate trial of Esomeprazole;
• active medical problems such as unstable seizures, or significant physical illness (e.g., serious liver or renal pathology).