A systematic review of nine trials found that the evidence for MDMA combined with psychotherapy as a treatment for PTSD is of moderate quality, while the evidence for ketamine—whether used alone for comorbid PTSD and depression or combined with psychotherapy—is very low to low. The review searched four databases for peer-reviewed literature up to October 2019 and included five ketamine and four MDMA trials. No trials of LSD or psilocybin met the inclusion criteria. The authors used a quality checklist and GRADE to rank the evidence, concluding that MDMA-assisted psychotherapy shows the strongest support among the psychedelics examined for reducing PTSD symptoms.
Psychedelic substances such as psilocybin, ayahuasca, LSD, and MDMA are gaining renewed medical interest due to the need for new psychiatric treatments and promising study results. This viewpoint reflects on the Royal Australian and New Zealand College of Psychiatrists' Clinical Memorandum on Psychedelics and notes regulatory developments, including applications for down-scheduling and access approvals. The authors argue that rigorous research is needed to assess benefits, safety, and therapeutic mechanisms. They summarize recent findings on mechanisms of action and the psychedelic-assisted psychotherapy model, suggesting medicinal psychedelics could become a new class of psychiatric treatments when used under medical supervision with psychotherapeutic support. However, sufficiently powered trials and safety protocols are required before clinical use, and untrained practitioner access could be harmful.