The mushrooming of the psychedelic renaissance: A scoping review identifying trends in ongoing clinical trials

Aims: The investigation of psychedelics as potential therapies has expanded dramatically in the past decade, leading to their study in a wide range of conditions. Here, we characterize all ongoing clinical trials utilizing a psychedelic intervention with the goals of identifying trends in experimental design and application and discuss how findings from individual, ongoing clinical trials may address current unanswered questions or recommendations from the field. Methods: A scoping review approach was used to identify registered clinical trials at ClinicalTrials.gov that listed a classic psychedelic as intervention criteria. All ongoing clinical trials were characterized by their study criteria, experimental design, and clinical trial status. When available, specific psychedelic analogs are included with their representative trial. Results: We identified 165 ongoing clinical trials that utilize a treatment intervention with a classic psychedelic. Most clinical trials were early phase, actively recruiting trials based in the United States for depression. Comparisons of experimental design criteria revealed that psychedelics are mostly administered a single time and use either an open-label, single-arm design, or a parallel-assignment, quadruple-blinded, active-placebo design. In our search, we found that only six trials explicitly report blinding effectiveness as a trial outcome and that 33 different placebos are being used as a control across psychedelic trials. Conclusion and Implications: Multiple clinical trials have been initiated that have the potential to shed insight on common critiques and unanswered questions in the field. Despite this, some areas warranting clarity remain, such as identifying a proper placebo or improving participant masking rates. We hope that insights from this review will help inform the reader of the status for clinical psychedelic research and inspire initiation of new clinical trials that may address the shortcomings discussed herein.