Directory

Ryan S. Sultan, MD, is a Columbia University psychiatrist and researcher specializing in addiction and mental health, playing a key role in the university’s initiative to combat the opioid crisis. Dr. Sultan is an Assistant Professor of Clinical Psychiatry in Columbia’s Department of Psychiatry and serves as a research scientist in the Division on Substance Use Disorders. He brings to the Columbia Center for Healing of Opioid and Other Substance Use Disorders – Intervention Development and Implementation (CHOSEN) a robust background in epidemiological research and clinical innovation. Dr. Sultan’s work focuses on understanding and addressing the negative health consequences of opioid and other substance use disorders, in line with CHOSEN’s mission to develop cutting-edge prevention and treatment interventions that reduce overdose deaths and improve public health. As Director of the Mental Health Informatics Lab at Columbia, he utilizes large-scale health data and informatics to identify trends and gaps in addiction treatment, helping to shape interventions that are both effective and implementable in real-world community settings. Clinically, he is a double board-certified Adult and Child Psychiatrist known for an integrative approach to care, directing Integrative Psychiatry, which provides personalized therapy and pharmacologic treatment for youth and adults with ADHD, substance use disorders, and co-occurring conditions. 

Dr. Sultan’s dual perspective as a frontline clinician and a data-driven researcher enables him to contribute practical insights to CHOSEN’s cross-disciplinary team. He has published and presented widely on topics ranging from youth ADHD medication trends to cannabis use outcomes and novel depression treatments. Through CHOSEN, Dr. Sultan collaborates with experts across social work, medicine, and public health to translate research into action, to pioneer projects that leverage AI to save lives, including efforts to model and predict opioid overdose risk as part of the fight against the opioid epidemic.

Dr. Kratz is interested in implementation of low-barrier models in the substance use disorder continuum of care, community-medical partnerships, and community-based participatory research. He is the founding Medical Director of the TRANSiT (“Therapeutic Resources and Assistance in Navigation to Services while in Transition”) program at NewYork-Presbyterian, a substance use bridge clinic and graduate medical education teaching site focused on low-barrier access to treatment for substance use disorders. He is also the Social Determinants of Health Champion for Columbia University Irving Medical Center and is the Medical Lead for Targeted Outreach in the NewYork-Presbyterian Division of Community and Population Health. Dr. Kratz is an Assistant Professor of Clinical Medicine at Columbia and is board-certified in Internal Medicine and Addiction Medicine.

Karli R. Hochstatter, PhD, MPH is an epidemiologist and health services researcher focused on the intersecting epidemics of substance use disorders, infectious diseases, and criminal justice involvement. Her research aims to improve the understanding and health of disadvantaged populations with substance use disorder using mixed-methods, social network strategies, and health services intervention approaches. She has worked on several NIDA-funded projects, including studies that aim to understand barriers and facilitators along the HIV and hepatitis C care continuums among criminal justice-involved adults. She has also extensively studied the use of mobile-health technology and computer-tailored interventions to reduce risk behaviors and increase health care utilization among people with substance use disorders. Dr. Hochstatter also has experience using molecular epidemiological surveillance data to detect and describe hepatitis C transmission networks. In her current work, she is building an understanding of how death investigation teams can aid in overdose prevention and linkage-to-care efforts.

Dr. Hochstatter completed her MPH and PhD in Population Health Sciences at the University of Wisconsin-Madison School of Medicine and Public Health and a postdoctoral fellowship in the HIV, Substance Abuse, and Criminal Justice T32 Fellowship Program at the Columbia University School of Social Work. She is also an alumna of the Criminal Justice Research Training Program on Substance Use, HIV, and Comorbidities at Brown University.

Dr. Hochstatter is currently a research scientist at Friends Research Institute and an affiliate of the Social Intervention Group (SIG) at CSSW. SIG projects she has worked on include: Project PACT, WORTH, and the HEALing Communities Studies.