Youth Advocacy & Research Collaborative

Sarah Bagley, MD

Professor of Medicine and Pediatrics, Boston University

Sarah Bagley is an associate Professor of Medicine and Pediatrics at Boston University School of Medicine and is board certified in Pediatrics, Internal Medicine, and Addiction Medicine. She is the founder of the CATALYST at Boston Medical Center providing integrated substance use care and primary care for youth where she sees patients. Her passion is to ensure that all youth who use substances have access to high quality, equitable care to promote their health. Her research focus is on the engagement of young adults who use drugs and their families in care to minimize risk for overdose and the complications of drug use. She has funding from the National Institute on Drug Abuse, the Centers for Disease Control and Prevention, and PCORI to conduct research about engagement in treatment and overdose prevention of young adults after nonfatal opioid overdose and reducing stimulant related overdose

Aditi Singh

Aditi Singh is a medical student at Boston University Chobanian & Avedisian School of Medicine. She holds a BA in neuroscience and a master’s in bioethics (MBE) from the University of Pennsylvania, where her capstone thesis explored the stigmatization of addiction and proposed policy reforms to improve substance use treatment systems in India. Her past research focused on sex differences in VTA GABA transmission during opioid withdrawal and the role of nitric oxide in withdrawal-related plasticity. She has worked as an EMT, a patient navigator for underserved populations, and a research assistant in addiction neuroscience. Aditi is passionate about addiction research, health equity, and improving care for underserved populations.

Ally Cogan, MPH

Research Project Manager

Ally Cogan is a research project manager for the YARC and the Clinical Addiction and Research Education Unit at Boston Medical Center. She assists in the management of day-to-day operations and activities on research programs focused on youth and young adult overdose prevention and harm reduction curriculum development. She received her MPH from Boston University School of Public Health, where she concentrated in community assessment, program development, implementation, and evaluation. She is passionate about the development of equitable access to tailored healthcare for underserved populations and those typically overlooked by healthcare systems, with specific passion for work with LGBTQIA+ folks. In her spare time she can be found biking, cuddling her cats, or engaging in some kind of fiber craft.

Amy Yule, MD

Dr. Amy Yule is board certified in adult, child, and addiction psychiatry. She is the Vice Chair of Addiction Psychiatry at Boston Medical Center and an Associate Professor at the Boston University School of Medicine. Dr. Yule works with youth with substance use disorders and co-occurring psychiatric disorders as well as their family in a multidisciplinary outpatient clinic. Her research is focused on decreasing risk associated with substance use for youth, preventing substance use disorders in youth with psychiatric disorders and treatment of co-occurring psychiatric and substance use disorders.

Cala Renehan, MPH

Cala Renehan is a research assistant at Boston Medical Center’s Clinical Addiction Research and Education Unit. Cala’s passion for harm reduction and overdose prevention stems from her time working at the Harm Reduction Action Center in Denver, CO. Her interest and commitment grew while she completed her MPH at Boston University. Cala has an enthusiasm for qualitative data and believes the best way to engage youth and young adults in harm reduction and overdose prevention is to simply talk to them and ensure they are heard. She feels privileged to carry out this work and contribute to work that ensures the safety and wellbeing of youth. 

Christina Freibott, PhD, MPH

Christina Freibott is a postdoctoral associate in the Department of Community Health Sciences at Boston University School of Public Health. She holds an MPH from Thomas Jefferson University and a PhD in Health Services and Policy Research from Boston University. Her work focuses on addressing the intersection of substance use and mental health among young adults, with a particular emphasis on college and university settings. She is committed to expanding access to evidence-based overdose prevention strategies, including naloxone training and distribution. Her research examines institutional approaches to opioid overdose prevention and how these can be improved to better support student populations.

Debbie M. Cheng, ScD

Debbie M. Cheng is assistant dean of data science and the founding executive director of the Center for Health Data Science at the Boston University School of Public Health. She is a professor of biostatistics with a research focus on applied statistics and the design and analysis of clinical trials. She collaborates with investigators worldwide on multiple studies in the areas of substance abuse and HIV. She is also associate director of the Providence/Boston Center for AIDS Research (CFAR) and co-director of its Biostatistics Core, as well as director of the Biostatistics and Data Management Core for the International URBAN ARCH Center, which aims to examine the impact of alcohol on multiple aspects of the TB disease continuum. Dr. Cheng is the lead statistician for the Massachusetts site of the HEALing Communities Study, a multi-site cluster randomized trial aimed at reducing opioid-related overdose deaths in communities across four different states, the largest study of its kind in addiction science.

Elvin Rosa

Research Assistant

Elvin Rosa is a Research Assistant for YARC and the Clinical Addiction Research and Education (CARE) Unit at Boston Medical Center. He supports the RETAIN Study, a pilot randomized controlled trial evaluating a motivational interviewing intervention to improve post discharge treatment retention among individuals with opioid use disorder (OUD) and serious injection-related infections (SIRIs). His work includes participant outreach, study visit coordination, and retention efforts through both in person and remote strategies. Outside of his research role, Elvin helps with overdose prevention workshops for youth and is working to expand these trainings across Boys and Girls Clubs throughout Massachusetts. As a former Club kid, the Boys and Girls Club is his greatest passion and source of support and he continues to give back through programming, mentorship, and community engagement. Elvin earned his BA in Biology with a minor in Public Health from Boston University in 2025 and is entering the Master of Arts in Medical Sciences (MAMS) program at BU School of Medicine starting in Fall 2025.

Jessica Calihan, MD, MSc

Jessie Calihan is a General Academic Pediatrics fellow in the Boston University Department of Pediatrics and provides primary and integrated substance use care for adolescents at Boston Medical Center. She completed the Urban Health Internal Medicine-Pediatrics residency program at Johns Hopkins Hospital prior to completing  fellowship training in Addiction Medicine and Adolescent Medicine at Boston Children's Hospital. Her clinical work focuses on providing high quality, accessible, and equitable care to promote youth health now and in their futures, and her research focuses on engaging families, particularly those affected by caregiver substance use, to prevent adolescent substance use and related harms. 

Kimberly Nelson, PhD, MPH

Kimberly Nelson is an associate professor of community health sciences at the Boston University School of Public Health and an associate professor of Psychiatry at Boston University School of Medicine. She is also faculty of the Fordham University Research Ethics Training Institute. As both a clinical psychologist and epidemiologist, Dr. Nelson focuses her research on understanding and intervening on psychological and structural determinants of health inequities with a particular focus on health inequities among marginalized adolescents and young adults. Additionally her work focuses on the ethical and legal issues involved in health research and interventions with adolescents and ways to use technology effectively and ethically for data collection and health promotion interventions.

Maurice Newman, MEd

Maurice currently serves as a Project Coordinator at the Centre for Biomedical Research Excellence (COBRE) on Opioid & Overdose, serving on the YES & CUTS studies respectively at Rhode Island Hospital, a member of Brown University Health. Maurice has a strong background in harm reduction, as he served at AIDS Project Worcester in various capacties such as Housing Case Manager, Drug Checking Technician, Phlebotomist, Street Outreach, Post Overdose Support Team member, Grant Writer, and Manager of Programs & Services. Maurice is driven by his personal philosphy - helping people becoming better versions of themselves. Maurice currently holds BEd in Elementary Education, MEd in Educational Leadership & Administration, and is pursing his PhD. in Organizational Leadership.

Moriah Wiggins

Research Coordinator

Moriah is the current research coordinator  for YARC and the Clinical Addiction and Research Education Unit at Boston Medical Center. She is a Boston native, and grew up in Boston’s South End neighborhood. She then attended the University of Massachusetts Dartmouth, where she received a Bachelor of Science in bioengineering. Upon receiving her undergraduate degree, Moriah served multiple lab roles at Foundation Medicine in Cambridge. During her time at Foundation Medicine, Moriah was also able to pursue her passions for D.E.I., health equity, and community engagement as the founding co-chair of the company’s first employee resource network for communities of color. When Moriah is not working, she wears the hat of a creative and immerses herself into Boston's thriving art communities.

Nina Cesare, PhD

Nina Cesare is a research scientist in the Biostatistics and Epidemiology Data Analytics Center within the Center for Health Data Science at Boston University. She arrived to public health with a PhD in sociology from the University of Washington, and works on a variety of projects that leverage a social determinants lens. In addition to quantitative research, Nina is an instructor at BU, where she teaches course addressing the fudamentals of public health, as well as sex, gender, and sexuality in global health.

Riley Coleman

Research Assistant

Riley is a research assistant for YARC and the Clinical Addiction and Research Education Unit at Boston Medical Center, and a public health and harm reduction enthusiast. Riley received their Bachelors of Science in Health Sciences from Boston University and has seven years of experience working in public health programming and research, with a special focus on substance use, mental health, harm reduction, HIV/infectious disease, and working with particular populations including youth and young adults, LGBTQIA+ people, and those who are unstably housed or experiencing homelessness. Riley is passionate about providing engaging evidence-based health education and when they're not working you can find them with their many pets, playing a new game with friends, or reading any number of books at the same time. 

Sarah Kosakowski, MPH

Associate Director of Research Operations

Sarah Kosakowski is the associate director of research operations for the YARC and the Clinical Addiction and Research Education Unit at Boston Medical Center. She oversees a large research program focused on opioid overdose prevention, behavioral interventions among people who use drugs and are at high risk of overdose, post overdose outreach, and harm reduction education development and implementation among youth and young adults. Additionally, she lead efforts within the Informatics Core on the HEALing Communities Study to integrate community engagement and data driven decision making approaches into developing and implementing evidence-based strategies to reduce opioid overdose fatalities in Massachusetts communities. Sarah received her MPH from Boston University School of Public Health, where she concentrated in health policy, law, and management, and is passionate about translating research findings and public health data to communities in usable, interactive, and digestible formats. In her spare time she likes to hike with her pup Cali, travel as much as she can, and exploring new cuisines

Traci Green, PhD, MSc