How I found my research: Exploring why some communities suffer the most from substance use disorders

David T. Zhu is an M.D.-Ph.D. student in the School of Medicine's Medical Scientist Training Program. Zhu recently published a paper in the JAMA Psychiatry journal showing that the widespread proliferation of fentanyl — with fentanyl-involved overdose deaths rising 100-fold among non-Hispanic Black individuals between 2010-2022 — is driving racial/ethnic disparities in substance use disorders.

The study aligns with Zhu’s broader research efforts to highlight critical gaps that must be addressed to advance social justice and health equity. In September, he wrote a commentary piece for the Richmond Times-Dispatch about rethinking the “war on drugs.”

Zhu shared with VCU News the ideas that drive his research and how he has refined his skills to become a better researcher.

Tell us the focus of your research ... and why it is important/impactful for all of us.

My work is driven by a core question: Why do certain communities — such as racial and ethnic minorities, individuals experiencing homelessness, and those living below the federal poverty line — shoulder a disproportionate burden of drug overdoses and substance use disorders? This inquiry fuels my research, which I approach from two complementary angles. On one hand, I delve into population health trends, seeking to investigate the underlying social and structural factors that perpetuate disparities in overdoses. On the other, I evaluate the implementation of harm reduction strategies on health outcomes and access to care — firmly believing that addiction, like diabetes and cardiovascular disease, must be recognized as a treatable chronic health condition deserving of empathy and advocacy. More broadly, I believe that these harm reduction policies translate into the fundamental belief that the overdose epidemic should be approached as a public health concern, rather than a criminal justice matter.

What inspired you to pursue this line of research?

When I started medical school at VCU, I became involved in research that analyzes regional variations in opioid prescriptions, overdose rates, hospitalizations and access to treatments like suboxone across Richmond's diverse census tracts. Our data revealed stark disparities: Neighborhoods separated by just a street or a single bus stop showed vastly different rates of overdoses and treatment availability. Witnessing these inequities so close to home deepened my commitment to public health research, with a focus on the prevalent social determinants that drive these outcomes.

My goal is to leverage this data to shape meaningful health policies and social programs to support individuals struggling with substance use disorders. Further, having grown up in Canada, where harm reduction programs like supervised consumption sites, needle exchange programs and safer supply initiatives have been implemented for decades, I’ve seen firsthand how these strategies reduce the harms of drug use and save lives. This international experience fuels my passion for advocating harm reduction policies in the U.S., drawing on global best practices to push for systemic change to combat the nation’s escalating overdose crisis. 

Tell us about a surprise in your research journey.

What struck me most during this research process was the profound impact of the stories I encountered — real people grappling with addiction or those who have lost someone to overdose — and how this fuels my advocacy work. Truthfully, working with public health data immerses you in a sea of numbers, p-values and statistical models, and it’s easy to get caught up in the middle of it all and view them as abstractions. But these figures are not just data points — they represent human lives. They represent the patients I encounter firsthand through my clinical shadowing and volunteering at VCU School of Medicine and fuel my commitment to engaging in research to improve health outcomes at a systemic level.

Standing at the crossroads of medicine and research is deeply humbling, reminding me that my work has the potential to transcend data and drive meaningful change through “social medicine.” By informing clinical interventions, bridging gaps in care, promoting harm reduction and reducing stigma, I hope that my research can ultimately shape policies that will support the recovery of those struggling with addiction.

Tell us about an obstacle or challenge you had to overcome in your work.

One of the hurdles I encountered during my research journey was acquiring coding and statistical expertise. As an undergraduate, I approached coding with reluctance, perceiving this as a tedious task and struggling to find its broader purpose. However, my perspective shifted as I became involved in research projects in need of these skills, which provided me with the motivation and sense of purpose to learn them through hands-on application.

For instance, one of my recent studies analyzed trends in private equity acquisitions of opioid treatment programs in the United States. Learning to code through online courses and guidance from my mentors equipped me with the critical skills to map geographic trends in these acquisitions over time. This work directly informs state-level policies aimed at better regulating private equity’s influence on the nation’s clinical infrastructure for addiction care, ensuring that opioid use disorder treatment remains patient-centered rather than financially driven. Additionally, coding has enabled me to perform statistical analyses to explore disparities across race, ethnicity, income and health insurance, uncovering the broader social inequities in health care access and outcomes. What once felt like a burden — coding and statistics — has now become a deeply fulfilling, purpose-driven part of my work.

Is there a memorable partnership or lesson you've embraced along the way?

During my medical school interviews, I had the chance to participate in three virtual lab visits, where I discussed my research aspirations with faculty. These conversations were pivotal in solidifying my decision to pursue an M.D./Ph.D. at VCU. The incredible faculty I met — Dr. Andrew Barnes, Dr. Peter Cunningham, Dr. Derek Chapman, Dr. Caitlin Martin, and others at the VCU School of Medicine and the VCU School of Public Health's Department of Health Policy — highlighted the positive research culture and collaborative environment that thrives here. But what makes a great mentor? One of my favorite reflections on mentorship comes from Dr. Suzanne Koven at Harvard Medical School: “A mentor is someone who has more imagination about you than you have about yourself.” This insight mirrors my own experience.

When I first embarked on my research journey, I was unfamiliar with the basics — how to conduct a literature review, design a study or even identify the right research questions. My mentors not only provided the scientific and technical expertise I needed, but also pushed me to think critically, embrace curiosity and build confidence. They cultivated an environment where I could learn from my mistakes while helping me see potential in myself that I hadn’t yet realized. Their belief in me has been nothing short of transformative, shaping my growth not only as a medical student and researcher, but also as a leader capable of lifting others up around me.

What do you find fulfilling about the research process? 

What makes research truly rewarding is its ability to drive advocacy beyond the four walls of the clinic. I’ve often listened to patients recount their struggles with addiction and substance use disorders, trapped in a system that limits their access to care — whether due to financial barriers, inaccessibility of treatment, pervasive societal stigma, or lack of a support system. Despite offering words of compassion and connecting them with social services in clinic, I've always found myself wanting to do more, which drew me to research, where I can expand the evidence base for informing policies that address the upstream social determinants of health.

For example, some of my recent work has highlighted how fentanyl is increasingly mixed with stimulants like cocaine and methamphetamine, creating a deadly “polysubstance” overdose epidemic that disproportionately affects racial and ethnic minorities. These data provide further scientific evidence to support efforts in expanding access to crucial harm reduction resources, such as naloxone, with the goal of reducing disparities and ensuring that compassionate, evidence-based care reaches the communities most in need.

What advice would you offer undergrads to kick-start their own research journeys?

Be persistent and open to learning. We all start off naive and inexperienced, but that’s part of the journey. Don’t hesitate to reach out to faculty at VCU or other institutions to see if they’d welcome you into their research. No task is too small. Learn from senior lab members and graduate students. Be insatiably curious. For every good research question I come up with, there are 20 more that fall flat. Focus on the burning questions that keep you up at night — the ones that make you want to learn more and drive real change. And always be kind and supportive. Research thrives on collaboration, and lifting others up will pay dividends in the long run. 

This article originally was published by VCU News. 

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