What the science says, what remains uncertain, and why we believe this work matters.
Psilocybin -- the naturally occurring compound found in certain species of mushrooms -- has been the subject of rigorous scientific investigation at some of the world's leading research institutions for over twenty years.
This research has been conducted under controlled clinical conditions with careful screening, standardized protocols, and validated outcome measures. It represents the foundation upon which Cedars and Spores has built its clinical approach.
By the Numbers
57–79%
of participants achieved clinically significant symptom reduction
Matos et al., 2026
80%
showed sustained improvement at six-month follow-up
Griffiths et al., 2016
70–91%
reported decreased fear of death after treatment
Barr et al., 2025
4.5 yrs
sustained benefits documented in long-term follow-up
Agin-Liebes et al., 2020
The Weight of Evidence
Beyond individual clinical trials, systematic reviews pool data across multiple studies to provide a more comprehensive picture. The following reviews specifically examine psilocybin-assisted therapy in palliative and end-of-life care.
Matos et al. (2026) -- Palliative Medicine
A systematic review of six clinical studies involving 74 participants with palliative care needs found that 57-79% of participants achieved a 50% or greater reduction in anxiety and depression symptoms. Effects persisted for six to eight months, with one study documenting sustained benefits at four and a half years. Adverse effects were mild and transient across all studies.
Palliative Medicine 2026;40(1):7-20 · 215 articles screened, 6 studies included
Yu et al. (2021) -- Psychiatry Investigation
A meta-analysis of five controlled studies found large and statistically significant reductions in both state and trait anxiety compared to placebo. Effects strengthened over the first two weeks and remained robust at six months. The analysis found no serious adverse events across all included trials. Transient blood pressure elevations were the most common physiological effect and resolved without intervention.
Psychiatry Investigation 2021;18(10):958-967 · Meta-analysis with random-effects model
Barr, Giese & Moreton (2025) -- Psychopharmacology
A scoping review of 31 studies examined how psychedelics affect attitudes toward death. Across studies, 70-91% of individuals reported decreased fear of death following psychedelic experiences. The depth of the experience -- particularly what researchers term “mystical-type experiences” -- was consistently linked to more positive shifts in attitudes toward death. The review also found that 3-17% of participants reported worsened death anxiety, underscoring the importance of clinical supervision.
Psychopharmacology 2025;242:1955-1976 · 31 studies reviewed
Landmark Trials
Center for Psychedelic and Consciousness Research
Griffiths et al. (2016)
A randomized, double-blind trial in 51 patients with life-threatening cancer diagnoses found that a single high-dose psilocybin session produced rapid and sustained decreases in anxiety and depression. At six-month follow-up, approximately 80% of participants continued to show clinically significant reductions in distress. Two-thirds of participants rated the experience among the top five most personally meaningful of their lives.
Journal of Psychopharmacology
Davis et al. (2021)
A randomized, waiting-list-controlled trial found that psilocybin-assisted therapy produced large, rapid, and sustained antidepressant effects in patients with major depressive disorder.
JAMA Psychiatry
Langone Center for Psychedelic Medicine
Ross et al. (2016)
A randomized, double-blind, placebo-controlled crossover trial in 29 patients found that a single dose of psilocybin produced immediate, substantial, and sustained improvements in anxiety and depression in patients with cancer-related psychiatric distress. The study reported large and significant decreases in death anxiety and increases in quality of life and life meaning.
Journal of Psychopharmacology
Agin-Liebes et al. (2020)
A long-term follow-up of the NYU trial found that reductions in anxiety and depression were sustained at 4.5-year follow-up in approximately 60-80% of participants -- the longest documented durability of psilocybin-assisted therapy outcomes to date.
Journal of Psychopharmacology
Centre for Psychedelic Research
Carhart-Harris et al. (2021)
A randomized, double-blind trial comparing psilocybin to the SSRI escitalopram for major depressive disorder. While the primary outcome measure did not reach statistical significance, secondary outcomes favored psilocybin on multiple measures.
New England Journal of Medicine
The Therapeutic Model
Psilocybin-assisted therapy is not simply taking a medication. It is a structured therapeutic process with three distinct phases, each of which contributes to outcomes.
Working with a trained therapist to establish trust, set intentions, and discuss what to expect. This phase creates the psychological safety that research consistently identifies as essential to positive outcomes.
The psilocybin experience itself, conducted in a comfortable and supportive environment with continuous professional supervision. Research shows that therapeutic benefit is closely tied to the quality of the setting and the therapeutic relationship.
Sessions afterward where a therapist helps process and make meaning of the experience. Integration is where insight becomes lasting change -- translating the experience into shifts in perspective, acceptance, and peace.
Clinical Safety
Across all published clinical research, psilocybin-assisted therapy has demonstrated a favorable safety profile when administered in supervised clinical settings with appropriate screening.
No serious adverse events
No serious adverse events have been reported in any published clinical trial of psilocybin for end-of-life distress.
Mild and transient effects
Commonly reported side effects include temporary blood pressure elevation, transient anxiety during the session, and occasional nausea or headache -- all self-resolving.
Supervised environment essential
Safety data applies to controlled clinical settings with trained professionals. Appropriate medical screening, psychological preparation, and continuous supervision are foundational.
Cedars and Spores is committed to advancing the evidence base for psilocybin-assisted therapy by using validated outcome measures, following established protocols, maintaining rigorous records, and supporting further research through de-identified outcome data contributions.
We believe that the responsible expansion of psilocybin-assisted therapy depends on honest, transparent reporting of outcomes -- including outcomes that are neutral or unfavorable.
Sources
The following peer-reviewed publications inform the content on this page. All claims are traceable to specific studies.
1Matos AR, Silva AC, Rego L, Fernandes R, Gonçalves S. Psilocybin-assisted therapy for individuals with palliative care needs: A systematic review of safety and efficacy. Palliative Medicine. 2026;40(1):7-20. doi:10.1177/02692163251383335
2Yu CL, Yang FC, Yang SN, et al. Psilocybin for end-of-life anxiety symptoms: A systematic review and meta-analysis. Psychiatry Investigation. 2021;18(10):958-967. doi:10.30773/pi.2021.0209
3Barr NNT, Giese KJ, Moreton SG. A scoping review of the effects of serotonergic psychedelics on attitudes towards death. Psychopharmacology. 2025;242:1955-1976. doi:10.1007/s00213-025-06787-x
4Cornish N, Garg A, McElwee MK. Psychedelics, spirituality, and existential distress in patients at the end of life. Cleveland Clinic Journal of Medicine. 2025;92(4):248-254. doi:10.3949/ccjm.92a.24100
5Rosenbaum D, Bhatt S, Bhatt A, et al. Psychedelics for psychological and existential distress in palliative and cancer care. Current Oncology. 2019;26(4):225-226. doi:10.3747/co.26.5009
6Griffiths RR, Johnson MW, Carducci MA, et al. Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. Journal of Psychopharmacology. 2016;30(12):1181-1197. doi:10.1177/0269881116675513
7Ross S, Bossis A, Guss J, et al. Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: A randomized controlled trial. Journal of Psychopharmacology. 2016;30(12):1165-1180. doi:10.1177/0269881116675512
8Agin-Liebes GI, Malone T, Yalch MM, et al. Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer. Journal of Psychopharmacology. 2020;34(2):155-166. doi:10.1177/0269881119897615
Important Disclaimer
The research summarized on this page represents published findings from academic clinical trials and peer-reviewed systematic reviews. These results were obtained under controlled research conditions and may not predict the outcome of any individual's experience. Psilocybin-assisted therapy is not approved by the U.S. Food and Drug Administration. Psilocybin remains a Schedule I substance under federal law. In Colorado, psilocybin-assisted therapy is permitted under the Natural Medicine Health Act through licensed healing centers. Cedars and Spores does not claim that psilocybin will produce any specific result for any individual.