Walter S. Mathis, MD

Stan Mathis, MD is the Medical Director of the Assertive Community Treatment (ACT) team at the Connecticut Mental Health Center and an Associate Professor in Yale’s Department of Psychiatry. Trained originally as an architect and urbanist, he brings a distinctive, systems-oriented perspective to psychiatry that integrates clinical care, data analytics, and the built and social environments in which patients live.

Clinically, Dr. Mathis provides community-based care to individuals with severe mental illness, working with patients in their homes and neighborhoods. In parallel, he has led substantial redesign of ACT team workflows and developed a suite of internally deployed digital tools - ranging from spatial and EHR-based analytics to telehealth access solutions - that have measurably improved clinical efficiency, outreach, and fidelity to evidence-based care. His clinical leadership has been repeatedly recognized with top evaluations from the Connecticut Department of Mental Health and Addiction Services.

As an educator, Dr. Mathis has played a central role in the development of Yale Psychiatry’s structural competency curriculum within the Social Justice and Health Equity program, contributing to a multi-year didactic series that integrates experiential learning, geospatial analysis, and historical context. He has also served as a research mentor and co–associate director of the Public Psychiatry Fellowship, supervising fellows’ scholarly projects and leading recruitment efforts, and he is actively involved in resident and medical student education across multiple programs.

Dr. Mathis’s research focuses on health services and equity, with an emphasis on advanced analytics—including geospatial methods, big data, machine learning, and large language models—to understand and reduce disparities in access, care pathways, and outcomes. His work spans serious mental illness, first-episode psychosis, pharmacy and specialty care access, and public health interventions, and has been published in leading peer-reviewed journals and presented nationally. He also serves as Director of Informatics for a multisite learning health collaborative for first-episode psychosis, where he develops scalable digital infrastructure to support continuous quality improvement at the system level.