Why Diversity Matters: Making Psychedelic Research More Inclusive

Psychedelic-assisted psychotherapy is showing remarkable promise for treating conditions like depression, PTSD, and addiction. However, a critical issue threatens to undermine this progress: the lack of diverse participants in clinical trials. A recent systematic review reveals that psychedelic research has a serious representation problem that could limit who ultimately benefits from these potentially groundbreaking treatments.

The Current State of Diversity in Psychedelic Research

A comprehensive review published in Psychiatry Research in March 2025 examined 24 randomized controlled trials of psilocybin and MDMA-assisted therapies, involving over 1,000 participants. The findings paint a concerning picture of who is—and isn't—being included in this research. The numbers are stark: Black/African-American participants made up only 2.2% of study participants, despite representing a much larger percentage of the general population. Hispanic/Latino participants were similarly underrepresented at just 7.2%. Overall, about 89% of participants in U.S. clinical psychedelic studies identified as non-Hispanic White—far higher than their 58% share of the U.S. population. It's not just racial and ethnic diversity that's lacking. The review found that while all studies reported participants' gender, only 9.5% reported sexual orientation, and a mere 4.8% reported immigration status. Not a single study reported participants' gender identity beyond the binary categories of male and female. Dr. Stephanie Haft, lead author of the review, explained: "Diverse samples are key for psychedelic-assisted therapy trials' generalizability. Without them, we simply don't know if these treatments work equally well for everyone."

Why This Matters for Patients

You might wonder why participant diversity in clinical trials matters so much. The answer is simple but profound: different groups may respond differently to the same treatment. Consider this example from another area of medicine: certain anticoagulant medications can vary in effectiveness depending on a person's ancestry, leading to significant differences in dosing requirements. Early trials that focused mainly on White populations missed this crucial variation, resulting in adverse outcomes for racial and ethnic minoritized groups after the medication was approved. Similar concerns exist for psychedelic therapy. Unlike many other treatments, psychedelic experiences are heavily influenced by a person's mindset, expectations, and cultural background—what researchers call "extra-pharmacological factors." This means that lived experiences of marginalization might significantly shape how different groups respond to these treatments. Some early evidence supports this concern. Naturalistic studies (which look at real-world use rather than controlled trials) have shown that the relationship between psychedelic use and mental health outcomes differs by race, ethnicity, and socioeconomic status. People from minoritized groups often report reduced benefits compared to white, affluent users. What makes this especially troubling is that many of the conditions being targeted by psychedelic research—like PTSD and depression—actually affect minoritized communities at higher rates. If these communities are excluded from research, they may end up with treatments that haven't been properly tested for their specific needs and contexts.

Barriers to Diverse Participation

Understanding why psychedelic research lacks diversity is the first step toward fixing the problem. The review identified several key barriers:

1. Time and Resource Constraints

Psychedelic clinical trials typically require multiple day-long sessions plus preparation and integration meetings. This substantial time commitment effectively excludes many people who can't take time off work, find childcare, or arrange transportation. People from lower socioeconomic backgrounds are particularly affected by these practical barriers.

2. Historical Context and Trust Issues

The history of psychedelic research and drug policy in the United States is deeply intertwined with racism and discrimination. The "War on Drugs" disproportionately targeted communities of color, and there have been troubling instances of unethical research practices against minoritized groups in the past. This history has created understandable mistrust of both drug research and the medical establishment in many communities.

3. Legal Concerns

Despite the controlled, legal nature of clinical trials, the fact that psychedelics remain criminalized substances in most jurisdictions creates additional concerns for potential participants. Given the reality of discriminatory policing practices, people from minoritized communities may be especially hesitant to participate in research involving controlled substances.

4. Cultural Factors

Cultural attitudes toward mental health treatment and substance use vary widely across different communities. Some potential participants may face stigma from their communities or have cultural frameworks that don't align with the predominantly Western, individualistic approach of most current psychedelic therapy protocols.

Solutions for More Inclusive Research

Creating more inclusive psychedelic research isn't just about identifying problems—it's about implementing solutions. Here are several approaches that researchers and institutions can adopt:

Improved Recruitment Strategies

Research teams can partner with community organizations, faith groups, and healthcare providers that serve diverse populations. Recruitment materials should be culturally sensitive and available in multiple languages. Additionally, researchers should consider where they advertise studies, ensuring they reach beyond predominantly white, affluent communities.

Reducing Practical Barriers

Offering evening and weekend appointments, providing transportation assistance, compensating participants fairly for their time, and offering childcare support can make participation more feasible for people with work and family responsibilities.

Building Trust Through Community Engagement

Meaningful community engagement means involving members of diverse communities in the research process from the beginning—not just as participants but as advisors, co-investigators, and therapists. This approach helps ensure that research protocols are culturally appropriate and address community concerns.

Training Diverse Therapists

The therapists who guide psychedelic sessions play a crucial role in creating a safe, supportive environment. Having therapists from diverse backgrounds who understand the cultural contexts and lived experiences of participants can significantly improve comfort and outcomes.

Transparent Reporting

Researchers should consistently collect and report comprehensive demographic data, including race, ethnicity, gender identity, sexual orientation, socioeconomic status, and disability status. This transparency helps identify gaps and track progress toward more inclusive research.

The Path Forward

The good news is that awareness of these issues is growing within the psychedelic research community. Some newer studies, particularly those involving MDMA, have made concerted efforts to recruit more diverse participant samples. However, much work remains to be done. As psychedelic therapies move closer to widespread approval and implementation, ensuring they work for everyone—not just the predominantly white, affluent populations currently represented in research—becomes increasingly urgent. Dr. Joshua Woolley, one of the co-authors of the review, emphasized this point: "If we want psychedelic therapy to help reduce rather than exacerbate health disparities, we need to make sure our research includes the full spectrum of people who might benefit from these treatments. "For those interested in psychedelic therapy, whether as potential patients, practitioners, or advocates, this research highlights the importance of asking questions about representation and inclusion. Who was included in the studies that demonstrated a treatment's effectiveness? How might different cultural contexts affect the therapy process? What steps are being taken to make these emerging treatments accessible to all communities? By asking these questions and supporting efforts to make psychedelic research more inclusive, we can help ensure that the benefits of these promising therapies are available to everyone who needs them—regardless of race, ethnicity, gender, sexuality, or socioeconomic status.

References

This article is based on research published in the following source: A systematic review of participant diversity in psychedelic-assisted psychotherapy trials

For more information about diversity in clinical trials more broadly, you can visit the FDA's Diversity in Clinical Trials Initiative .

To learn more about ongoing efforts to increase diversity in psychedelic research, visit the Chacruna Institute's Racial Equity and Access Committee .