Most psilocybin therapy trials use a one-on-one format, one patient, one or two therapists, one session. A new Phase 1 study from the University of New Mexico is testing whether that model is necessary, or whether group-format psilocybin-assisted therapy can work for PTSD.
The official trial title is Group Psilocybin-Assisted Therapy for Post-Traumatic Stress Disorder, abbreviated GPAT on the ClinicalTrials.gov record. It is an open-label Phase 1 study with estimated enrollment of 36 participants, sponsored by the University of New Mexico and listed under principal investigator Lawrence Leeman. The trial is not yet recruiting, with an estimated start date of May 2026 and primary completion date of May 2027.
The design is more specific than the original short post suggested. According to the trial record, participants receive two group-format psilocybin sessions scheduled four weeks apart. The primary goals are still basic, safety, feasibility, study completion, adverse events, and preliminary signal on PTSD severity through CAPS-5 and PCL-5. But UNM's study page makes clear the format is not simply group dosing for efficiency. It is built around peers with similar background or trauma histories, with trained peer facilitators working alongside licensed therapists.
That added detail matters because it changes what kind of scalability question this really is. The study is not asking whether psychedelic care can be made cheaper by packing more people into a room. It is asking whether a group structure might itself be therapeutically useful for trauma-exposed populations who may benefit from shared context and mutual recognition.
UNM's participant-facing framing is also more concrete than the bare registry entry. The study is aimed at cohorts that include veterans, first responders, and women survivors of sexual violence, and UNM says the protocol was developed with community input. The site also describes a broader collaboration set around the project, including UCB-CEP, PMHA, Heroic Hearts Project, SNaP Lab, and BCHEC.
Why this matters
The group format question is fundamentally a scalability question. Individual psilocybin therapy is expensive, it requires trained therapists, extended session time, and a tightly controlled environment. Delivering that at any meaningful scale, especially in public-health or trauma-care settings, is a major operational constraint.
If group delivery proves safe and workable, the economics change substantially. But this trial is interesting for a second reason. It is testing a model that treats shared background and peer support as part of the intervention design, not just a cost-saving compromise.
That does not mean the group format will work. Phase 1 is still the earliest clinical stage, and the study is open-label, small, and not yet recruiting. But it is a more ambitious design question than the original one-link version of the post captured. If the study produces a useful signal, it could shape how future psilocybin programs are designed for real-world trauma care rather than boutique one-on-one settings.