Postdoctoral Fellows

Brandy Henry, Ph.D.

Dr. Henry is a clinician scientist who uses her years of practice experience to inform her research which aims to improve the health of criminalized populations. Her unique combination of research and practice experience led to her appointment by the Governor of Massachusetts to the state’s Restrictive Housing Oversight Committee which oversees housing conditions in Massachusetts’ prisons and jails. Dr. Henry also serves on the board of directors of multiple grass roots non-profits which provide direct services to incarcerated and formerly incarcerated people. Her work in these roles acts to ground her research in the complexity of translating research to inform policy and practice.

Dr. Henry received her Doctorate in Social Policy (Behavioral Health track) in 2019, and her Master of Arts degree in Social Policy (Behavioral Health track) in 2017 from the Brandeis University Heller School for Social Policy and Management.  While at Brandeis, she was awarded a Brandeis University Heller School Doctoral Fellowship (2018-2019), a Harvard Kennedy School Rappaport Institute Public Policy Summer Fellowship (2016), and a Ruth L. Kirschstein Predoctoral Individual National Research Service Award from the National Institute on Alcohol Abuse and Alcoholism (2015-2018). Dr. Henry also received a Master of Social Welfare degree from the University of California Los Angeles (UCLA) in 2012, and is a Licensed Independent Clinical Social Worker (LICSW) in the state of Massachusetts.  She earned a Bachelor of Arts degree in the field of Psychology, with minors in Statistics and Biology at Boston University (2006).

Dr. Henry’s uses both qualitative and quantitative methods and has expertise in collecting data via in depth interviews with currently incarcerated people, policy-makers, and clinicians. She has also conducted big data analysis of a secondary data using latent class analysis and structural equation modeling. Her work has documented social determinants of incarceration with a focus on the role of trauma for incarcerated people  with mental health, and substance use disorders She has also been involved with NIDA funded Juvenile Justice Translational Research on Interventions for Adolescents in the Legal System (JJ-TRIALS) studies. Her work on these studies has examined implementation of organizational supports for screening, assessment, and referral to substance use, mental health & HIV treatment in juvenile justice systems . Dr. Henry has also published in the areas of private prisons, Hepatitis C drug pricing, and drug courts

At Columbia she has been involved with the HEALing Communities, Intersecciones , and PACT studies. While at Columbia, Dr. Henry has also published on COVID-19 and its intersections with overdose and incarceration .

Karli Hochstatter, Ph.D., MPH

Karli Hochstatter, PhD, MPH, received her Doctorate in Population Health Sciences with a PhD minor in Criminal Justice Health (2019) and Master of Public Health (2015) from the University of Wisconsin School of Medicine and Public Health. As a predoctoral candidate, Dr. Hochstatter was also a scholar in the NIDA-funded Criminal Justice Research Training Program on Substance Use, HIV, and Comorbidities at Brown University. During her graduate studies, she also served as an assistant for the UW Cooperative Extension Opioid Task Force, disseminating evidence-based opioid overdose prevention interventions to community coalitions across Wisconsin. She also earned a Bachelor of Science degree in the field of Biology, with a minor in Global Health, at the University of Wisconsin – Madison (2013).

Dr. Hochstatter’s research interests include prevention and linkage to medical care for HIV and hepatitis C virus among populations disproportionately burdened by substance use disorders, with a special focus on people who inject drugs and criminal justice-involved adults. She has worked on several NIDA-funded research projects addressing these intersecting epidemics of injection drug use and infectious diseases. Her dissertation research focused on using mobile health technology to improve hepatitis C and HIV-related outcomes and prevent overdose death among people with opioid use disorder, as well as computer-tailored risk-reduction interventions that improve the health of people who inject drugs in harm reduction settings. She also served as project manager for a longitudinal cohort study of HIV-positive persons transitioning from prison to community-based care. In addition to this work, Dr. Hochstatter worked on using Global Hepatitis Outbreak Surveillance Technology, a tool recently developed by the CDC, to characterize hepatitis C transmission clusters among social networks of people who inject drugs and incarcerated persons.

While at Columbia, Dr. Hochstatter has examined illicit substance use and engagement in treatment among women releasing from community supervision programs. Her work has also focused on the influences of the COVID-19 pandemic on drug use and HIV care, as well as racial and ethnic disparities in receipt of medical care among people with substance use disorders releasing from prison. Dr. Hochstatter will continue to develop, implement, and disseminate innovative strategies to prevent the negative consequences of the opioid epidemic and improve treatment engagement among justice-involved adults.

Melissa Slavin, Ph.D.

Dr. Slavin received her Doctorate of Philosophy (2019) and Master of Arts (2017) in Clinical Psychology from the University at Albany.  She completed her predoctoral internship at the Veterans Affairs Connecticut Healthcare System in West Haven.  Prior to this, she received her Bachelor of Arts in Psychology with a minor in Criminal Justice from the University of Connecticut.  Dr. Slavin is passionate about advocating for drug policy reform that reduces overcriminalization of non-violent offenses.  Her research has focused on identifying intrapersonal (e.g., cognitive expectancies, motivational states, personality traits) and interpersonal (e.g., sexual abuse, physical violence) factors associated with substance misuse and addictive behaviors, including problematic gambling and compulsive sexual behavior.  She intends for her research to inform prevention measures and harm reduction interventions that can be used as alternatives to incarceration. Her dissertation examined the effects of harsh restrictions on “psychological reactance”, a motivational state characterized by negative affect and cognition that may influence individuals’ substance use.  Dr. Slavin would like to continue research on personal and environmental risk and protective factors for addiction, particularly among justice-involved individuals.


Kristi Stringer, Ph.D.

Dr. Stringer received her Doctorate in Medical Sociology (2017) and her Master of Arts degree in Sociology (2012) from the University of Alabama at Birmingham (UAB). She earned her Bachelor of Science in the field of Psychology at Middle Tennessee State University in 2009. During her tenure at UAB, Dr. Stringer was an AHRQ pre-doctoral fellow at the Center for Outcomes and Effectiveness Research and Education in UAB’s Division of Preventive Medicine and was awarded a Ruth L. Kirschstein NRSA Individual Predoctoral Fellowship (F31) from the National Institute of Drug Abuse in 2014. Dr. Stringer’s research agenda focuses on the impact of health related stigmas on the HIV treatment cascade and the development of stigma reduction interventions aimed at increasing HIV prevention and treatment adherence behaviors. Her dissertation research utilized a mixed-methods approach to understand the adverse effects of substance use stigma and HIV-related stigma on adherence to antiretroviral medications and retention in HIV care among drug involved people living with HIV (PLWH). During her post-doctoral training at Columbia University, Dr. Stringer plans to adapt a stigma reduction intervention to address health related stigmas experienced within healthcare environments among drug involved PLWH in Kazakhstan through Columbia’s collaboration with the Global Health Research Center of Central Asia (GHRCCA).

Predoctoral Fellows

Christina Aivadyan

Christina is a doctoral student at the Columbia University School of Social Work who conducts policy-relevant substance use and HIV prevention research tailored to the developmental context of adolescents and young adults. Her research explores social determinants of substance use and sexual risk behaviors, and the ways in which public health laws and policies may serve as structural drivers of HIV transmission for young people.  Christina has extensive clinical and epidemiological research experience focused on substance use and co-occurring psychiatric disorders. Prior to her doctoral studies, Christina was a Project Director at the New York State Psychiatric Institute, where she managed numerous large-scale research projects, including a validation study of DSM-5 alcohol, drug, and psychiatric disorders in the National Epidemiologic Survey on Alcohol and Related Conditions-III, a FDA-mandated validation study of a version of the Psychiatric Research Interview for Substance and Mental Disorders designed to assess DSM-5 opioid use disorder among chronic pain patients, and a longitudinal study of the reliability and validity of DSM-5 substance use disorder criteria in community and patient samples. Additionally, as a Study Coordinator and Counselor in the Columbia University Department of Psychiatry, Christina contributed to the development of a motivational interviewing-based brief technological intervention for alcohol and marijuana use and sexual risk behaviors among homeless young adults and oversaw the randomized controlled trial evaluating its feasibility and preliminary efficacy. During her pre-doctoral training, Christina has evaluated the ways in which age and developmental stage differentially affect the relationship between substance use and sexual risk behavior among Black men who have sex with men at disproportionate risk for HIV. Her recent work examines the association between state laws and policies relevant to equality for sexual minorities and suicide attempts among LGBTQ adolescents in the Youth Risk Behavior Surveillance System. Christina plans to utilize a mixed-methods approach to examine the influence of state-level laws on consent and confidentiality in sexual health services on self-reported HIV testing among U.S. adolescents in her dissertation research.  Christina received her Master of Science degree in Social Work from Columbia University in 2013, her Bachelor of Arts degree in Psychology from New York University in 2007, and is a Licensed Master Social Worker in the state of New York.

Ariel Marie Shirley Richer

Ariel Richer is a doctoral student at the Columbia University School of Social Work working within the Social Intervention Group (SIG). Her research focuses on prevention of intimate partner violence, drug and alcohol use, and HIV/STI risk factors. Additionally, she engages in community-based participatory research and works collaboratively with Indigenous and Native communities, as well as women who are involved with the justice system. She works under the direction of Associate Professor Louisa Gilbert, PhD on project eWORTH  (Multimedia HIV/STI Intervention for Black Drug-Involved Women on Probation in New York City) and project WINGS  (Computerized service tool to address partner abuse among women in drug court).

Previously, she worked as an Impact Evaluator at the federal agency, Administration for Native Americans within Health and Human Services working directly with community-based organizations developing logic models, evaluation plans, data collection tools, and processes at a community level, across a diverse set of communities. She is fiercely committed to addressing gender-based issues at large, especially gender-based violence, and has over seven years of experience within domestic violence organizations, sexual assault resource centers, and economic enhancement programs for survivors of trafficking and domestic violence. Ariel is a co-founder and Director of Research and Advocacy for the Urban Indigenous Collective , an Indigenous-led non-profit committed to the mental health of Urban-living Native and Indigenous folks in the NYC tri-state area. Finally, she is a co-founder of ShockTalk, a telehealth app to connect Indigenous folks with Indigenous mental health providers.

She earned her Master of Science in Social Work, Social Enterprise Administration from Columbia University School of Social work in 2015 and is a Licensed Master Social Worker.

Ruth Shefner

Ruth Shefner is a doctoral student in Sociomedical Sciences at the Mailman School of Public Health, on the sociology track. She is focused broadly on criminal legal systems, with interests in policing, court based interventions, and collateral consequences of mass incarceration. Prior to coming to Columbia, Ruth was the Director of the Goldring Reentry Initiative, a program housed at the University of Pennsylvania’s School of Social Policy and Practice that supports individuals pre- and post-release from Philadelphia’s county jail system while training Master of Social Work students to work in the field of criminal justice. In this role, Ruth provided direct therapeutic case management services, as well as oversaw all program operations, including client selection, collaboration of community and legal partners, clinical supervision of social work students, and program evaluation. She completed her Master of Social Work and Master of Public Health at the University of Pennsylvania, where she conducted research related to opioid overdose and criminal justice contact, and supported the evaluation of Philadelphia’s prearrest diversion program pilot initiative. She graduated from Brown University in 2013 with a Bachelors of Arts in Public Health.

Tara McCrimmon

Tara McCrimmon is a doctoral student (DrPH) in the Sociomedical Sciences Department at the Mailman School of Public Health. Previously, she worked as a project director for the Global Health Research Center of Central Asia, where she managed two HIV prevention and treatment intervention trials based in Almaty, Kazakhstan. Her research interests include healthcare access among key populations, structural interventions, health and social policy, and implementation science. Tara holds an MPH from Columbia’s Mailman School of Public Health, an MIA from Columbia’s School of International and Public Affairs, and a BA from the University of Chicago

Former Fellows