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Psilocybin research: what the evidence shows

The primary psychoactive compound in psilocybin mushrooms, studied most heavily as an assisted therapy for depression, anxiety, and addiction.

State of the evidence

Synthesized

Synthesized from 25 studies in the library · AI-generated, grounded in the abstracts below

Found by searching the library for Psilocybin, magic mushrooms, psilocin, psychedelic mushrooms, then ranked by relevance.

Psilocybin, given with psychological support, shows consistent short-term reductions in depression and anxiety across randomized and open-label trials, with the largest controlled trial finding a 25 mg dose outperformed a 1 mg control at three weeks but not at twelve weeks. Effects appear rapid and often sustained for months in cancer-related distress and treatment-resistant depression, though several key studies are small, open-label, or lack active comparators, and one head-to-head trial found no significant difference versus escitalopram. Durability, the specific drug effect, and long-term safety remain uncertain.

Evidence by study

Direction is which way each study's own result points, not our rating of the study.

What the directions mean
Supports:
the study found the intervention worked, or its hypothesis held.
Opposes:
it found the opposite, no benefit or a harm.
No effect:
no significant difference either way.
Mixed:
effects in both directions within the same study.
Unclear:
the abstract does not report a direction.
Study Design Sample size Direction Finding
Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial 2016 RCT 51 Supports High-dose psilocybin produced large decreases in depressed mood and anxiety, with about 80% showing clinically significant improvement sustained at 6 months.
Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial 2016 RCT 29 Supports Single-dose psilocybin with psychotherapy produced rapid, substantial improvements in anxiety and depression, with 60-80% showing clinically significant reductions at 6.5 months.
Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance 2006 double-blind study 36 Supports Psilocybin occasioned mystical-type experiences rated as having substantial personal meaning and spiritual significance at 2 months.
Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study. 2016 open-label feasibility trial 12 Supports Psilocybin was well tolerated and associated with marked reductions in depressive symptoms at one week and three months.
Trial of Psilocybin versus Escitalopram for Depression 2021 RCT No effect No significant difference in antidepressant effects between psilocybin and escitalopram at week 6, though secondary outcomes generally favored psilocybin without correction for multiple comparisons.
Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder 2020 RCT 24 Supports Psilocybin with supportive psychotherapy produced large reductions in depression severity versus a waiting-list control, with 71% response at week 1 and 54% remission at week 4.
Pilot Study of Psilocybin Treatment for Anxiety in Patients With Advanced-Stage Cancer 2010 double-blind placebo-controlled study 12 Supports Psilocybin was safe and associated with significant reductions in anxiety at 1 and 3 months and improved mood.
Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin 2012 within-subjects placebo-controlled fMRI study 30 Supports Psilocybin decreased cerebral blood flow and BOLD signal in hub regions and reduced mPFC-PCC connectivity, with the magnitude of ACC/mPFC decrease predicting subjective effect intensity.
Psilocybin-assisted treatment for alcohol dependence: A proof-of-concept study 2015 single-group proof-of-concept study 10 Supports Abstinence increased significantly after psilocybin administration and gains were largely maintained to 36 weeks.
REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics 2019 theoretical Supports Argues that psychedelics relax the precision of high-level priors, enabling revision of pathologically overweighted beliefs underlying mental illness.
Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression. 2022 phase 2 double-blind RCT 233 Supports A single 25 mg dose significantly reduced depression scores at three weeks versus a 1 mg control, while 10 mg did not; sustained response at 12 weeks was not clearly supported.
Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action 1998 experimental study Opposes Psilocybin produced a psychosis-like syndrome that was blocked by serotonin-2A antagonists but increased by a dopamine antagonist, implicating serotonin-2A activation.
Psilocybin with psychological support for treatment-resistant depression: six-month follow-up. 2017 open-label trial 20 Supports Two psilocybin doses produced large reductions in depressive symptoms that remained significant at 3 and 6 months.
Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects. 2011 RCT 18 Supports 20 and 30 mg/70 kg psilocybin occasioned mystical-type experiences with persisting positive changes in attitudes, mood, and behavior at 14 months, though 39% experienced extreme anxiety/fear at high doses.
Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction 2014 open-label pilot study 15 Supports 80% of participants showed seven-day point prevalence abstinence at 6-month follow-up after psilocybin-assisted smoking cessation treatment.
Psilocybin and Inflammatory and Mitochondrial Stress Markers in Parkinson Disease 2026 nonrandomized clinical trial Unclear Assesses associations between psilocybin therapy and changes in systemic markers of inflammation and mitochondrial stress; no results are reported in the abstract.
Psilocybin in Treatment-Resistant Depression: Weighing Rapid Antidepressant Effects Against Uncertain Durability 2026 structured narrative review Mixed Concludes psilocybin with psychological support shows short-term antidepressant activity, but notes one phase 3 trial met its week-3 endpoint while another did not confirm its week-6 hypothesis, leaving specific drug effect and durability uncertain.
Investigation of the pharmacological and circuit basis for psychedelic drug effects on interval timing in mice. 2026 experimental animal study Supports Psilocin altered timing accuracy and precision, an effect blocked by a 5-HT2A antagonist but not a 5-HT1A antagonist, implicating 5-HT2A receptors in timing effects.
Serotonin 1B receptors expressed on forebrain excitatory neurons mediate the post-acute anxiolytic response to psilocybin in mice. 2026 controlled animal experiment Supports Mice lacking 5-HT1B receptors on forebrain excitatory neurons showed intact acute responses but strongly attenuated post-acute anxiolytic effects to psilocybin.
Language-associated brain representations covary with disruption of selfhood under psilocybin 2026 observational fMRI study 43 Supports Greater similarity in activity of a left-lateralized frontotemporal language network under psilocybin was associated with higher ego-dissolution scores.
Group psilocybin in an integrative retreat setting enhances social connection: an observational case report 2026 case study 14 Supports Participants showed significant increases in perceived social connectedness and significant decreases in distress after group psilocybin ceremonies.
The Follow-Up Problem in Psilocybin-Assisted Therapy: Integration, Aftercare, and the Missing Standard 2026 commentary Unclear Argues that integration, aftercare, and long-term follow-up in psilocybin-assisted therapy remain poorly defined compared with short-term outcome measurement.
The Hidden Therapeutic Bridge: Exploring Psilocybin’s Role in Depression, Inflammation, and Pain – A Narrative Review 2026 narrative review Supports Argues that psilocybin shows therapeutic potential for depression, anxiety, and pain, with mechanisms possibly involving inflammation, pain processing, the default mode network, and mystical experiences.
Mechanistic Evaluation of Psilocybin in Neurodegenerative Disorders: Relevance of 5-HT2A Receptors and Downstream Pathways 2026 review Supports Argues that psilocybin shows promise for neurodegenerative disorders via 5-HT2A-mediated neuroplasticity and neuroinflammation effects, citing preclinical and emerging clinical evidence, while calling for randomized trials.
Participant experiences and recommendations for psychedelic clinical trials and future treatment delivery: a qualitative study with experts by experience from the Psychedelic Participant Advocacy Network 2026 qualitative study 4 Mixed Participants described trial procedures as shaping their experiences and reported loss or frustration after study ending, recommending structured peer support.

Points of agreement

  • Multiple controlled and open-label trials report rapid reductions in depression and anxiety after psilocybin with psychological support.
  • Benefits in cancer-related distress and treatment-resistant depression are often sustained for months in follow-up.
  • The intensity of the acute psychedelic or mystical experience is repeatedly reported to predict therapeutic response.
  • Animal and human imaging work links psilocybin's effects to 5-HT2A receptor activation and altered brain network activity.

Conflicts

  • The largest phase 2 trial found a dose-dependent antidepressant effect at three weeks but did not clearly support sustained response at twelve weeks, while smaller open-label studies report durable benefits.
  • One head-to-head trial found no significant difference between psilocybin and escitalopram, whereas secondary outcomes and other trials suggest psilocybin advantages.
  • A phase 3 review notes one trial met its primary endpoint while another did not confirm its week-6 hypothesis, leaving the specific drug effect uncertain.

Gaps

  • Durability beyond six to twelve months and retreatment strategy are largely unstudied.
  • Blinding is difficult with psychedelics, and several key trials are open-label or lack active comparators.
  • Sample sizes in most efficacy trials are small.
  • Long-term safety, including psychosis-like effects and cardiovascular outcomes, is not well characterized.
  • Integration, aftercare, and post-trial support standards are poorly defined.
  • Populations studied are narrow, mostly treatment-resistant depression and cancer distress, with little on neurodegenerative disease or group settings.
Browse these studies in the library

Common questions

What does the research agree on about psilocybin?
  • Multiple controlled and open-label trials report rapid reductions in depression and anxiety after psilocybin with psychological support.
  • Benefits in cancer-related distress and treatment-resistant depression are often sustained for months in follow-up.
  • The intensity of the acute psychedelic or mystical experience is repeatedly reported to predict therapeutic response.
  • Animal and human imaging work links psilocybin's effects to 5-HT2A receptor activation and altered brain network activity.
Where do studies on psilocybin conflict?
  • The largest phase 2 trial found a dose-dependent antidepressant effect at three weeks but did not clearly support sustained response at twelve weeks, while smaller open-label studies report durable benefits.
  • One head-to-head trial found no significant difference between psilocybin and escitalopram, whereas secondary outcomes and other trials suggest psilocybin advantages.
  • A phase 3 review notes one trial met its primary endpoint while another did not confirm its week-6 hypothesis, leaving the specific drug effect uncertain.
What is still unknown about psilocybin?
  • Durability beyond six to twelve months and retreatment strategy are largely unstudied.
  • Blinding is difficult with psychedelics, and several key trials are open-label or lack active comparators.
  • Sample sizes in most efficacy trials are small.
  • Long-term safety, including psychosis-like effects and cardiovascular outcomes, is not well characterized.
  • Integration, aftercare, and post-trial support standards are poorly defined.
  • Populations studied are narrow, mostly treatment-resistant depression and cancer distress, with little on neurodegenerative disease or group settings.
How we analyze this

This synthesis reads the 15 most-cited and 10 most recent studies whose primary subject is Psilocybin, up to 25 in all. The most-cited set anchors the established evidence, and the recent set surfaces work that is too new to have gathered citations yet.

A study qualifies only when Psilocybin or a known alias appears in its title or keywords, so broad reviews that mention it only in passing are left out. Each study is read from its abstract, strongest evidence first, and the summary reports the direction of the results along with any conflicts and gaps.

The full method, including what a person does and does not review, is on the methods page.

Ask your own question in the Research Synthesis Tool

Latest monthly recap: September 2026 →

4,389 articles · 1,711 from the last two years · 14,666,659 participants across 1,395 studies reporting sample size

Common study designs

review 928 systematic review 235 experimental study 238 randomized controlled trial 155 theoretical or philosophical paper 285

Psilocybin research by condition and practice

Data updated

Studies whose primary subject is both Psilocybin and the condition or practice, with reviews counted by the study design extracted from each abstract. Registered trials are from ClinicalTrials.gov. This maps how much research exists, not how well anything works.

Psilocybin research by condition and practice: studies, meta-analyses and systematic reviews, registered clinical trials, the highest trial phase, and studies from the last two years. Most studies first.
Condition or practice Studies Meta-analyses and systematic reviews Registered trials Highest phase From the last two years
Depression 505 studies 86 meta-analyses and systematic reviews 100 registered trials up to Phase 3 220 from the last two years
Anxiety 308 studies 47 meta-analyses and systematic reviews 20 registered trials up to Phase 2 86 from the last two years
Psychedelic-assisted therapy 250 studies 32 meta-analyses and systematic reviews 23 registered trials up to Phase 2 93 from the last two years
Addiction 184 studies 24 meta-analyses and systematic reviews 36 registered trials up to Phase 3 56 from the last two years
Microdosing 56 studies 5 meta-analyses and systematic reviews 5 registered trials up to Phase 2 24 from the last two years
PTSD 48 studies 4 meta-analyses and systematic reviews 25 registered trials up to Phase 3 20 from the last two years
Meditation 39 studies 2 meta-analyses and systematic reviews 7 registered trials up to Phase 2 10 from the last two years
End-of-life distress 37 studies 2 meta-analyses and systematic reviews 6 registered trials up to Phase 3 20 from the last two years

Research volume by year

Compare topics →

2,749 studies whose primary subject is psilocybin since 2002

Studies about psilocybin per year, 2002 to 2026, peaking at 530 in 2025 Bar chart: one bar per year, taller where more studies were published that year. 0 300 600 2005 2010 2015 2020 2025
2026 is partial
Show the numbers
Studies about psilocybin per year, 2002 to 2026, peaking at 530 in 2025
Year Studies
2002 11
2003 7
2004 6
2005 10
2006 15
2007 6
2008 7
2009 10
2010 15
2011 11
2012 24
2013 22
2014 20
2015 31
2016 41
2017 44
2018 63
2019 60
2020 123
2021 177
2022 277
2023 375
2024 378
2025 530
2026 486

Research

Synthesize the evidence → Search all →

Connectedness as a candidate pathway linking psilocybin retreat experiences to sustained wellbeing: a prospective naturalistic study

Frontiers in Psychiatry October 28, 2026 Maria Åkesson, Pehr Granqvist, Robert Johansson et al.

BackgroundPsychedelic retreats are increasingly used to promote wellbeing outside clinical settings, yet the psychological processes associated with sustained improvements in wellbeing remain poorly understood. From a public mental health perspective, identifying mechanisms that support positive mental health beyond symptom reduction is of growing importance.MethodsThis naturalistic...

DOI: 10.3389/fpsyt.2026.1924069 (opens in new tab) Full text (opens in new tab) Psilocybin Connectedness Mystical experiences Psychedelics +2

Substantial Treatment-Seeking Interest, Narrow Eligibility: Diagnostic Heterogeneity and External Validity in the PRIDE Psilocybin Trial—Relevance to Precision Psychiatry

Behavioral Sciences October 26, 2026 Antonio Inserra, Luca Persico, Arianna Rosati et al.

Public and patient interest in psychedelic-assisted psychotherapy is increasing, but people seeking access to psychedelic trials may be more clinically heterogeneous than the populations these trials can enrol. We conducted a cross-sectional descriptive analysis of previously unreported aggregate telephone-screening data from the coordinating site of PRIDE, an ongoing Italian multicentre phase...

DOI: 10.3390/bs16111997 (opens in new tab)

Sex-related differences in outcomes following psilocybin or escitalopram: a Bayesian secondary analysis.

Psychopharmacology October 26, 2026 Aline Frick, Grace Blest‐hopley, Manesh Girn et al.

Major depressive disorder (MDD) shows marked sex differences in prevalence, symptomatology, and treatment response. However, females remain underrepresented in many clinical trials, and sex-specific treatment outcomes are rarely examined. This study reanalyzed data from a randomized controlled trial comparing psilocybin and escitalopram for MDD to evaluate sex differences across multiple...

DOI: 10.1007/s00213-026-07177-7 (opens in new tab) Full text (opens in new tab) Anxiety Major depressive disorder Psilocybin Anhedonia +3

The Post-Acute Window: Suicidal Ideation and Behaviour After Psilocybin. A Rapid Computational Evidence Synthesis

Zenodo (CERN European Organization for Nuclear Research) October 24, 2026 Odin Loch preprint

Background. Averaging the mean change in a suicidality score can hide a subgroup whose suicidal thoughts worsen in a particular stretch of days after psilocybin. Trials often do not enrol people with psychosis, bipolar disorder, or current high suicide risk. Objective. To assemble, from public sources only, what can actually be counted about treatment-emergent suicidal ideation or behaviour in...

DOI: 10.5281/zenodo.23612453 (opens in new tab)

Psilocybin in Treatment-Resistant Depression: Weighing Rapid Antidepressant Effects Against Uncertain Durability

Therapeutics October 19, 2026 Lukasz Szarpak, Michal Pruc, Dorota Jablonska-Moczulo et al.

Background/Objectives: Treatment-resistant depression (TRD) is heterogeneous and recurrent. Psilocybin administered with structured psychological support can reduce symptoms rapidly. Support protocols differ in content and intensity, and trial design complicates estimates of the specific drug effect and durability. We reviewed efficacy, durability, mechanisms, safety, and clinical delivery in...

DOI: 10.3390/therapeutics3040021 (opens in new tab)

Serotonin 1B receptors expressed on forebrain excitatory neurons mediate the post-acute anxiolytic response to psilocybin in mice.

Psychopharmacology October 17, 2026 Sixtine Fleury, Yian Shang, Katherine M. Nautiyal

Psilocybin can produce rapid and sustained antidepressant-like and anxiolytic effects, yet the receptor and circuit mechanisms underlying these behavioral changes remain unclear. While the serotonin 2A receptor mediates psilocybin's acute psychedelic effects, psilocin (the active metabolite of psilocybin) binds many serotonin receptor subtypes. Our prior work has identified the serotonin 1B...

DOI: 10.1007/s00213-026-07184-8 (opens in new tab) Full text (opens in new tab) Anxiety Psilocybin 5-ht1br Desynchrony +2

Mechanistic Evaluation of Psilocybin in Neurodegenerative Disorders: Relevance of 5-HT2A Receptors and Downstream Pathways

CNS & Neurological Disorders - Drug Targets October 14, 2026 Sheekha Chaudhary, Sanchit Dhankhar, Monika Saini et al.

More than fifty million individuals worldwide are experiencing neurodegenerative disorders, which include Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease, multiple sclerosis, and frontotemporal dementia. These disorders have a significant role in the gradual degradation of cognition and motor skills. Most current treatment approaches have little...

DOI: 10.2174/0118715273491538261009064612 (opens in new tab)

The Hidden Therapeutic Bridge: Exploring Psilocybin’s Role in Depression, Inflammation, and Pain – A Narrative Review

Current Neuropharmacology October 14, 2026 Mareli Vázquez-Barreto, Mariana Ugarte-Rocha, Abraham Flores Vargas et al.

Mental disorders are among the leading causes of non-fatal health loss worldwide and are associated with significant individual, social, and economic burdens. On the other hand, neuropathic pain affects approximately 7-8% of the world's adult population and is a leading reason for medical consultations. A bidirectional relationship between depression and pain has been widely documented....

DOI: 10.2174/011570159x513731260923101459 (opens in new tab)

The Follow-Up Problem in Psilocybin-Assisted Therapy: Integration, Aftercare, and the Missing Standard

Zenodo (CERN European Organization for Nuclear Research) October 14, 2026 Cacho Ernesto preprint

As psilocybin-assisted therapy becomes increasingly standardized in measuring short-term clinical outcomes, the processes that follow the psychedelic experience remain far less defined. This paper examines integration, aftercare, and long-term follow-up from clinical trials to real-world implementation in Oregon and Colorado, identifying critical gaps and opportunities to better understand,...

DOI: 10.5281/zenodo.23376467 (opens in new tab)

Clinical trials

All Psilocybin trials →