Thersa Costales, MD
Theresa Costales, MD
Chief Medical Officer, AHCCCS
Dr. Theresa Costales is a board-certified psychiatrist and the Chief Medical Officer of the Arizona Health Care Cost Containment System (AHCCCS), Arizona’s Medicaid agency. In this role, she leads clinical strategy and oversight for healthcare service delivery to the over two million Arizonans enrolled in Medicaid.
Prior to joining AHCCCS in January 2025, Dr. Costales served as the Arizona Medical Director for Connections Health Solutions, where she oversaw clinical operations at the Urgent Psychiatric Center in Phoenix and the Crisis Response Center in Tucson. Her leadership focused on improving outcomes for individuals with serious mental illness (SMI), particularly those involved in the civil commitment process.
Dr. Costales earned her Bachelor of Science in Biology from Canisius College and her medical degree from Georgetown University School of Medicine. She completed her psychiatry residency at the Icahn School of Medicine at Mount Sinai in New York City, serving as administrative chief resident in her final year.
Known for her dedication to improving the quality of services provided via systemic reform, Dr. Costales has partnered with stakeholders across Arizona to address gaps in behavioral health care and champion patient-centered solutions.