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Center Faculty

The core faculty for the Center for Mental Health and Addiction Policy Research at the Johns Hopkins Bloomberg School of Public Health and Johns Hopkins School of Medicine are conducting services and systems research to improve the lives of persons with mental illness and addiction. Meet our faculty:

Headshot of Caleb Alexander

G. Caleb Alexandar, MD, MS

G. Caleb Alexander is an Associate Professor of Epidemiology and Medicine at Johns Hopkins Bloomberg School of Public Health, where he serves as a founding co-Director of the Center for Drug Safety and Effectiveness. He is a practicing general internist and pharmacoepidemiologist and is internationally recognized for his research examining prescription drug utilization. Alexander’s research focuses on population-based patterns and determinants of pharmaceutical use, clinical decision-making regarding prescription drugs, and the impact of changes in regulatory and payment policy on pharmaceutical utilization. In addition to expertise conducting survey-based investigations, he has also extensive experience with the analysis of secondary data sources including administrative claims and large national surveys. Alexander received his B.A. cum laude from the University of Pennsylvania, an MD from Case Western Reserve University, and a Master of Science from the University of Chicago.

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Renan Castillo, PhD

Renan Castillo is a health services researcher with expertise in the study of disability and trauma outcomes, psychosocial determinants of disability, and extensive experience coordinating multi- institutional studies in the trauma setting. He currently serves as the Deputy Director for the Coordinating Center of the Major Extremity Trauma Research Consortium (METRC), a group of over 60 hospitals conducting over a dozen clinical trials in orthopaedic trauma. He is the PI of both an NIH R01 multicenter validation the PROMIS tools in the trauma setting, and a DOD funded multicenter evaluation of the efficacy of multimodal pharmacologic therapy to reduce pain and opioid utilization following orthopaedic surgery. Castillo is working on the development of tools to identify low back pain patients at risk for failure to return to work, and to track adherence to treatment guidelines following occupational injuries. Castillo has substantial expertise in psychometrics, and has participated in the development and validation of the Trauma Stages of Change Questionnaire, the Hopkins Rehabilitation Engagement Rating Scale, and Multidimensional Surgical Pain Scale.

Headshot of Gail Daumit.

Gail Daumit, MD, MHS

Gail Daumit is a practicing general internist, epidemiologist and clinical researcher at the Johns Hopkins University Medical Institutions.  She is an associate professor with a primary appointment in the Department of Medicine and joint appointments in the Departments of Psychiatry and in Epidemiology, Health Policy and Management, and Mental Health in the Bloomberg School of Public Health. She Associate Director of in the Welch Center for Prevention, Epidemiology and Clinical Research. Daumit received a Bachelor of Science in Economics at the University of Pennsylvania Wharton School of Business, her MD from Emory University School of Medicine, and completed her Internal Medicine Residency at Massachusetts General Hospital. She then came to Johns Hopkins as a Robert Wood Johnson Clinical Scholar and General Medicine Fellow and completed her MHS in Epidemiology before joining the faculty. Daumit’s research program uses clinical epidemiology and health services research methods to focus on improving physical health and decreasing premature mortality in persons with serious mental illnesses.

Headshot of Kenneth Feder.

Kenneth A. Feder, PhD

Kenneth A. Feder, PhD, is an assistant scientist in the Department of Mental Health. His research is focused on evaluating policy and programmatic responses to the United States' opioid epidemic. An additional current area of research is how the COVID-19 pandemic has affected health outcomes and service access for adults with substance use disorder. From 2019-2021, Feder served as the Center for Disease Control and Prevention's Epidemic Intelligence Service Officer (EIS) assigned to Maryland's Department of Health, where he coordinated several aspects of Maryland's response to the COVID-19 pandemic.

Headshot of Michael Fingerhood.

Michael I. Fingerhood, MD

Michael I. Fingerhood is an associate professor of Medicine and Chief of the Division of Chemical Dependence at Johns Hopkins Bayview Medical Center. He earned his Bachelor of Arts degree from Johns Hopkins University and his Medical Degree from the Albert Einstein College of Medicine. He completed internal medicine training and a chief resident year at Johns Hopkins Bayview Medical Center. The mission of his career has been to promote and improve the provision of medical care to patients with substance abuse, including the treatment of HIV and hepatitis C, with the development, maintenance and evaluation of innovative programs related to the care of these individuals. Fingerhood created the Comprehensive Care Practice, a primary care practice largely devoted to providing primary care to individuals with substance use disorder. The practice has been innovative in integrating buprenorphine treatment into the primary care setting for over 450 individuals. Fingerhood’s research interests also include contingency management and the use of a therapeutic workplace as part of treatment for substance use disorder. He has co-authored, “The American Society of Addiction Medicine Handbook of Addiction Medicine.”

Joseph J. Gallo, MD, MPH

Joseph Gallo, MD

Joseph Gallo focuses on the form and course of depression among older adults. Using the data from the NIMH Epidemiologic Catchment Area surveys, Gallo carried out a series of studies using novel statistical modeling to explore how depression presents differently among older adults than younger persons. The spectrum studies, a series of proposals using mixed methods, built on these findings to carry out a mixed methods study of how older adults experience depression. A second major area of research has involved mental health treatment in primary care settings including medical comorbidity. He is the Principal Investigator for a long-term follow-up of PROSPECT (Prevention of Suicide in Primary Care Elderly – Collaborative Trial), a randomized trial of depression management in primary care practices. A third major area of research involves the use of mixed methods in health services research. He also is the Principal Investigator for a new Mixed Methods Research Training Program for the Health Sciences, bringing scholars and mentors in mixed methods together to advance the research employing mixed methods in the health sciences. Gallo was a member of the 2011 working group to provide guidelines for best practices for mixed methods proposals for NIH.

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Darrell J. Gaskin, PhDg

Darrell J. Gaskin is Associate Professor of Health Economics and Deputy Director of the Center for Health Disparities Solutions at the Bloomberg School of Public Health in the Department of Health Policy and Management at the Johns Hopkins University.  He is an internationally known expert in healthcare disparities, access to care for vulnerable populations, and safety net hospitals. His goal is to identify and understand barriers to care for vulnerable populations; to develop and promote policies and practices that improve access to care for the poor, minorities and other vulnerable populations; and to eliminate race, ethnic, socioeconomic and geographic disparities in health and healthcare.  

Headshot of Nathan Irvin.

Nathan Irvin, MD

Nathan Irvin is an assistant professor in the Department of Emergency Medicine. He earned a medical degree from Harvard Medical School in 2003 and following medical school, he completed a residency in emergency medicine at Alameda County Medical Center’s Highland Hospital in Oakland, California, where he was a chief resident, prior to graduating in 2011. Upon completion of residency, Irvin entered into the Robert Wood Johnson Foundation’s Clinical Scholars Program at the University of Pennsylvania, graduating in 2013 with a masters degree in health policy research.

Irvin is on faculty in the Department of Emergency Medicine and holds interests in social emergency medicine — a burgeoning field that seeks to explore the biopsychosocial issues that patients living in urban communities disproportionately face. Using this framework, he has participated in and led several efforts to improve the health of patients living in Baltimore. Furthermore, Irvin is passionate about violence prevention and the psychological effects of trauma and serves as a co-PI on the East Baltimore Community Trauma Response program, which aspires to make Johns Hopkins Health System and the East Baltimore community more trauma informed and trauma responsive. Irvin is also the director of the newly minted social emergency medicine 4th year resident Focused Advanced Specialty Training (FAST) opportunity for the Johns Hopkins residency.

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John W. Jackson, ScD

John W. Jackson is an epidemiologist whose interests span pharmacoepidemiology, mental health, and health disparities.  He is particularly focused on developing and applying causal inference methods to understand the etiology of disparities in mental health treatment and their relation to disparities in long-term recovery, functioning, and co-morbidity. This research program aims to provide evidence that can target further research and interventions to bring about equitable mental health. His second area of focus is to build and disseminate conceptually grounded diagnostic tools to help stakeholders assess the validity of epidemiologic and clinical studies, particularly those that examine complex exposures and also how their effects are mediated. His work heavily draws on causal inference areas related to longitudinal data, propensity scores, and instrumental variables, and effect decomposition.

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Renee M. Johnson, PhD, MPH

Renee M. Johnson is an assistant professor in the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health. A social scientist by training, her research addresses violence and substance use among adolescents and emerging adults. Much of her work involves marginalized populations including people of color, LGBT youth, and youth in low-income, urban areas. Johnson’s current work examines changes in the prevalence of marijuana use among adolescents and emerging adults in relation to the dynamic landscape of marijuana policy. She earned a BA from Spelman College, and a PhD from the University of North Carolina Gillings School of Global Public Health. 

Headshot of Jill Marsteller.

Jill Marsteller, PhD

Jill Marsteller is associate professor of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health. She specializes in evaluation of quality improvement programs and organizational behavior research, specifically in estimating the influence of organizational variables on quality improvement activities in hospitals and primary care practices. She uses both quantitative and qualitative research methods to investigate determinants of successful implementation, dissemination, and sustainability of knowledge. Among areas she has investigated are culture and climate in healthcare settings and measurement of context and implementation. She has experience with both implementation and evaluation of learning networks and collaboratives. In addition, she is presently the Associate Director for Quality and Patient Safety of the Center for Health Services and Outcomes Research and sits on the Executive Committee of the Armstrong Institute for Patient Safety and Quality in the Johns Hopkins School of Medicine.

Headshot of Ramin Mojtabai.

Ramin Mojtabai, MD

Ramin Mojtabai is a professor in the Department of Mental Health, Bloomberg School of Public Health, with joint appointment in the Department of Psychiatry. He is a practicing psychiatrist in the Community Psychiatry Clinic at Johns Hopkins Hospital and teaches an introductory course on mental health services. Mojtabai’s research focuses on patterns of mental health treatment seeking in the community, the extent and correlates of unmet need for mental health care and barriers to such care including stigma and financial barriers. He has been involved in a number of studies examining trends in the use of services and especially the use of psychotropic medications in the US and other countries. 

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Daniel Polsky, PhD

Daniel Polsky is the 40th Bloomberg Distinguished Professor of Health Economics and Policy at Johns Hopkins University. He holds primary appointments in both the Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health and the Carey Business School. He is the Director of the Hopkins Business of Health Initiative. Dr. Polsky a national leader in the field of health policy and economics, has dedicated his career to exploring how health care is organized, managed, financed, and delivered, especially for low-income populations. His own research has advanced our understanding of the cost and quality tradeoff of interventions whether they are changes to large federal programs or local programs. He is a member of the National Academy of Medicine. He serves on the Congressional Budget Office’s Panel of Health Advisers and was the senior economist on health issues at the President’s Council of Economic Advisers. He received a Master of Public Policy degree from the University of Michigan in 1989 and a PhD in economics from the University of Pennsylvania in 1996.

Headshot of Brendan Saloner.

Brendan Saloner, PhD

Brendan Saloner is an assistant professor in the Department of Health Policy and Management at the Bloomberg School of Public Health, and also holds appointments in the Department of Mental Health and the Berman Institute of Bioethics.  Saloner is interested in access to mental health and substance abuse treatment, as well as the impact of state and national health reforms on the financing, delivery, and availability of behavioral health services.  His previous work has explored the impact of the Affordable Care Act young adult provision on mental health care use. He has also explored disparities in the treatment of addiction disorders, attention-deficit/hyperactivity disorder, and the use of antipsychotic medications in the Medicaid program. Beyond behavioral health, Saloner has interests in issues related to the equity of health care, and has written about fairness in health care financing.

Joshua M. Sharfstein, MD

Joshua M. Sharfstein is the Inaugural Director of the Bloomberg American Health Initiative and Professor of the Practice in the Department of Health Policy and Management. Previously, he served as the Secretary of the Maryland Department of Health and Mental Hygiene, Principal Deputy Commissioner of the U.S. Food and Drug Administration, Commissioner of Health for Baltimore City, and as health policy advisor for Congressman Henry A. Waxman.

Headshot of Susan Sherman.

Susan Sherman, PhD, MPH

Susan Sherman is a professor in the Department of Health, Behavior, and Society with secondary appointments in the Department of Population, Family and Reductive Health as well as Epidemiology at the Bloomberg School of Public Health.  She co-directs the Addiction and Overdose focus area of the Bloomberg American Health Initiative. She also co-directs the Center for AIDS Research’s (CFAR) Baltimore efforts, through the Baltimore HIV Collaborative. Sherman has published extensively on improving the health of drug users and sex workers through both observational and intervention research. She has conducted several large peer outreach and micro-enterprise HIV prevention, randomized trials in Thailand, India, Baltimore, and Pakistan. In Baltimore, she currently is examining the effects of policing on the HIV risk of street-based sex workers as well as leading a combination HIV prevention community-empowerment intervention with this population, anchored by a full-service community drop-in center.  

Headshot of Kenneth Stoller.

Kenneth Stoller, MD

Kenneth Stoller is an assistant professor of Psychiatry and Behavioral Sciences at the Johns Hopkins University School of Medicine, where he received his medical degree and completed psychiatric residency and addiction psychiatry fellowship. As a Medical Director of Addiction Treatment Services at Hopkins Bayview, he was the recipient of a 5-year NIH-funded K23 grant focusing on cost and adherence in drug abuse treatment. In 2009, Stoller assumed Directorship of the Johns Hopkins Hospital Broadway Center for Addiction. His expertise is in substance use problems, particularly medication assisted therapies. His early work on basic human laboratory studies of buprenorphine was followed by work on evidence-based treatments and payor policies. This body of work centered on improving outcome while controlling costs by identifying and treating substance use disorders, and through integrating and coordinating co-occurring somatic, mental health, chronic pain, and addiction disorders.

Headshot of Kayla Tormohlen.

Kayla N. Tormohlen, PhD, MPH

Kayla Tormohlen is an assistant scientist in the Department of Health Policy and Management. She conducts research in the area of substance use and mental health services, and is interested in understanding and eliminating barriers to service utilization. Additionally, her work examines impacts of substance use policies, particularly those aimed at addressing the opioid crisis in the United States. Tormohlen received her BA from the University of Northern Colorado, and her MPH and PhD in public mental health and substance use epidemiology from the Johns Hopkins Bloomberg School of Public Health.

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Daniel W. Webster, ScD, MPH

Daniel Webster is professor of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health where he serves as Director of the Center for Gun Policy and Research and as Deputy Director for the Center for the Prevention of Youth Violence. Webster is one of the nation’s leading experts on gun policy and the prevention of gun violence. He is a widely sought out source of information and insight on the topic for news media, policymakers, and public safety officials. Webster has led evaluations of a broad range of interventions including policies regulating firearms, prescription drugs, and alcohol; policing and criminal justice initiatives designed to reduce gun violence; street outreach and conflict mediation programs with high-risk groups; and interventions to identify, educate, and refer victims of intimate partner violence at highest risk for lethal violence.  

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Andrea S. Young, PhD

Andrea S. Young is an assistant professor in the Department of Psychiatry and Behavioral Sciences, Division of Child and Adolescent Psychiatry at Johns Hopkins University School of Medicine. Young is a practicing clinical psychologist in the Department of Psychiatry at KKI. She earned her PhD in clinical psychology from Duke University and completed her pre-doctoral internship in the Virginia Commonwealth University Health System. Young completed a postdoctoral research fellowship in child and adolescent mood disorders at The Ohio State University. Her research interests include access to child mental health services as well as service use patterns, correlates, and long-term outcomes. She has also been involved in research examining the longitudinal course of and interventions for childhood mood disorders.