Beyond Efficacy Signals: Regulatory, Methodological, and Translational Challenges in Clinical Research on Ketamine and Psilocybin in Psychiatry
Damian Swieczkowski, Michal Pruc, Lukasz Szarpak, Aleksander Kwaśny, Wiesław Jerzy Cubała
Psychiatry International September 1, 2026 DOI: 10.3390/psychiatryint7050190 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Structured narrative review Peer reviewed |
|---|---|
| Topics | Esketamine Ketamine Psilocybin |
| Key findings | The review identifies recurring weaknesses across six author-conducted studies and the wider literature, including protocol design, dose and endpoint selection, masking and expectancy, safety monitoring, treatment context reporting, participant diversity, and consent comprehensibility. It concludes that ketamine has a more mature evidence and implementation base than psilocybin, and that responsible translation requires integrated evidence across multiple domains. |
Abstract
Major depressive disorder (MDD) and treatment-resistant depression (TRD) continue to drive interest in ketamine-family compounds and psilocybin, but antidepressant efficacy alone does not establish whether these interventions can be evaluated reliably or implemented responsibly. We conducted a structured narrative review using targeted PubMed/MEDLINE searches through 21 July 2026, hand-searching of reference lists, and review of current regulatory documents. Six studies conducted by the authors formed the empirical foundation, covering trial protocols, dose–response relationships, treatment context reporting, regulatory alignment, participant diversity, and informed-consent readability. Findings were synthesized across regulatory, internal methodological, contextual, external, ethical, and implementation domains. The six studies identified recurring weaknesses in protocol design, dose and endpoint selection, masking and expectancy assessment, safety monitoring and long-term follow-up, reporting of psychological support and treatment setting, participant representativeness, and consent comprehensibility. The wider literature broadly supports these conclusions. Ketamine has a more mature evidence and implementation base, whereas psilocybin remains at an earlier stage of clinical development. Responsible translation into clinical practice therefore requires integrated evidence addressing efficacy, causal validity, safety, treatment context, diversity, informed consent, durability, and service delivery, while clearly distinguishing legal requirements, regulatory guidance, evidence-based methodological practices, and the authors’ recommendations.
Comparable studies
Other narrative reviews on psilocybin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function. General population | 2019 | Integrative review | |
| The pharmacology of psilocybin | 2002 | Review | |
| Serotonin research: contributions to understanding psychoses | 2008 | Review | |
| Psychedelics, Meditation, and Self-Consciousness | 2018 | Review | |
| The abuse potential of medical psilocybin according to the 8 factors of the Controlled Substances Act | 2018 | Review |
Citations in the library
Cites 37
- Antidepressant Efficacy of Ketamine in Treatment-Resistant Major Depression: A Two-Site Randomized Controlled Trial American Journal of Psychiatry August 28, 2013
- Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression. New England Journal of Medicine November 3, 2022
- Single-Dose Psilocybin Treatment for Major Depressive Disorder JAMA August 31, 2023
- Ketamine for rapid reduction of suicidal thoughts in major depression: a midazolam-controlled randomized clinical trial American Journal of Psychiatry December 5, 2017
- Efficacy and safety of psilocybin-assisted treatment for major depressive disorder: Prospective 12-month follow-up Journal of Psychopharmacology February 1, 2022
and 32 more in the library