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Psilocybin

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, particularly at higher doses (20-30 mg) and combined with psychological support, shows rapid and sustained reductions in depression and anxiety in patients with life-threatening cancer and treatment-resistant depression, with effects lasting up to 6-12 months in open-label and controlled trials. A meta-analysis of six RCTs confirms standard-dose psilocybin is superior to control conditions for major depressive disorder, though a head-to-head trial found no significant difference versus escitalopram at 6 weeks. The evidence is promising but limited by small sample sizes, open-label designs, and lack of long-term durability data beyond 12 months.

Confidence in the evidence

Moderate
  • Multiple RCTs and a meta-analysis (6 RCTs) show consistent positive effects for depression and anxiety, but many studies are small (12-79 participants) and some are open-label.
  • The largest head-to-head trial (psilocybin vs. escitalopram) found no significant difference on the primary outcome, introducing some inconsistency.
  • Most trials include psychological support, making it difficult to isolate the drug effect from the therapeutic context, and blinding is often inadequate.
  • Long-term follow-up data are limited to 6-12 months, and durability beyond that is unknown.
How we rate confidence

Confidence reflects the strength of the underlying evidence, not whether the result is favorable. It weighs the number and size of studies, their design (randomized trials count for more than observational or single-case work), how consistently they point the same way, and their risk of bias.

Tiers run from Insufficient to High. High is rare in this field: small, early, or open-label studies land lower even when their direction is encouraging.

Evidence by study

Direction is each study's finding relative to your question: Supports, Opposes, No effect, Mixed, or Unclear.

High-dose psilocybin produced large decreases in depression and anxiety, sustained at 6 months with ~80% showing clinically significant improvement.

RCT · Sample size: 51

Single-dose psilocybin produced immediate, substantial, and sustained improvements in anxiety and depression, with 60-80% maintaining reductions at 6.5 months.

RCT · Sample size: 29

Psilocybin produced rapid and sustained antidepressant effects in treatment-resistant depression, with no control group.

open-label feasibility study · Sample size: 12

No significant difference in antidepressant effects between psilocybin and escitalopram at week 6 on the primary outcome, though secondary outcomes favored psilocybin.

RCT

Two psilocybin sessions produced large antidepressant effects in MDD compared to a waiting-list control.

RCT · Sample size: 27

Psilocybin significantly reduced anxiety at 1 and 3 months and improved depression at 6 months, with no serious adverse events.

RCT · Sample size: 12

Psilocybin decreased cerebral blood flow and BOLD signal in hub regions like the thalamus and cingulate cortex, with decreased mPFC-PCC coupling predicting subjective effects.

observational (fMRI) · Sample size: 30

Psilocybin significantly increased abstinence from alcohol after administration, with gains largely maintained up to 36 weeks.

proof-of-concept study · Sample size: 10

Proposes the REBUS model: psychedelics relax the precision of high-level priors, enabling revision of maladaptive beliefs underlying mental illness.

theoretical

25 mg psilocybin significantly reduced depression at week 3 vs. 1 mg control, but sustained response at 12 weeks was not significant.

RCT · Sample size: 233

Psilocybin induces a psychosis-like syndrome in humans, blocked by a serotonin-2A antagonist, suggesting a role for 5-HT2A overactivity in schizophrenia.

observational

Psilocybin produced large reductions in depressive symptoms at 5 weeks (Cohen's d=2.3) that remained significant at 6 months (d=1.4).

open-label trial · Sample size: 20

Psilocybin at 20-30 mg/70 kg occasioned mystical-type experiences in 72% of volunteers, with sustained positive changes in attitudes, mood, and behavior at 14 months.

RCT · Sample size: 18

80% of participants showed seven-day point prevalence abstinence at 6-month follow-up after psilocybin-assisted smoking cessation treatment.

open-label pilot study · Sample size: 15

Psilocybin increased the personality trait of Openness, sustained over 1 year in those who had mystical experiences.

RCT

Psilocybin produced sustained improvements in anxiety (59% reduction at week 3) and quality of life through 12 months, though effects were not significant after accounting for depression improvement.

open-label trial · Sample size: 15

Study investigates the role of the serotonin 5-HT2A receptor in psilocin's effect on social behavior deficits in mice.

preclinical (animal)

Therapeutic alliance had weaker direct effects on depression outcomes than the psychedelic experience itself, but alliance influenced the psychedelic experience.

post hoc analysis of RCT · Sample size: 79

Reviews psilocybin's potential for tinnitus via 5-HT2A receptor activation, glutamate release, and BDNF upregulation, restoring neural plasticity.

review

Standard-dose psilocybin was superior to control in reducing depressive symptoms (SMD: -1.05) and associated with higher response and remission rates at 2-3 weeks.

meta-analysis

Identified reporting gaps in psilocybin trials: overrepresentation of prior psychedelic users, inconsistent reporting of therapy sessions, and lack of blinding success assessment.

descriptive review

Protocol for a study exploring psilocybin's acceptability and safety in bipolar II depression, a population typically excluded from trials.

protocol (open-label feasibility study)

Female participants reported more intense acute subjective effects and impairment under psilocybin than males, independent of drug concentration.

pooled analysis of two RCTs · Sample size: 72

Psilocybin induced c-Fos expression in the nucleus accumbens, with 5-HT2A and 5-HT2B receptors mediating effects in neurons and non-neuronal cells.

preclinical (animal)

Study aims to characterize sex-specific effects of psilocybin on brain and behavior after developmental stress in a mouse model.

preclinical (animal)

Points of agreement

  • Psilocybin, especially at higher doses (20-30 mg), produces rapid and substantial reductions in depression and anxiety in cancer patients and those with treatment-resistant depression.
  • The therapeutic effects are often sustained for months (6-12 months) after a single or two doses.
  • The quality of the acute psychedelic experience (e.g., mystical-type experience) is consistently associated with better clinical outcomes.
  • Psilocybin is generally well-tolerated in controlled settings, with no serious adverse events reported in most trials.

Conflicts

  • One large RCT found no significant difference between psilocybin and escitalopram for depression at 6 weeks, while other trials show large effects versus placebo or waiting-list controls.
  • Sustained response at 12 weeks was not significant in one phase 2 trial, whereas other studies report maintained benefits up to 12 months.
  • Psilocybin can induce acute anxiety and psychosis-like symptoms in some individuals, contrasting with its therapeutic effects.

Gaps

  • Long-term durability beyond 12 months is unknown.
  • Most trials exclude patients with bipolar disorder, suicidality, or psychosis, limiting generalizability.
  • Blinding success, therapist fidelity, and expectancy effects are rarely reported, making it hard to isolate drug effects from psychological support.
  • Sex differences in response are understudied, with preliminary evidence suggesting females may experience more intense acute effects.
  • Optimal dosing, number of sessions, and the role of psychotherapy components remain unclear.
Browse these studies in the library
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.

4,225 articles · 1,613 from the last two years · 9,158,089 participants across 1,153 studies reporting sample size

Common study designs

review 778 systematic review 200 experimental study 232 cross-sectional survey 137 theoretical or philosophical paper 226

Legalizing Magic Mushrooms: A Different Set of Laws for a Different Kind of Drug

Edward S. Adams

This article examines how the cannabis industry is regulated, tracing its origins, history, and flaws. It then compares the cannabis and psilocybin industries, arguing that the cannabis regulatory model should not be copied for psilocybin. Instead, the author proposes customized regulatory approaches that address psilocybin's distinct features, aiming to create a safe, effective, and well-regulated market.

The Birth of the Psychedelic Industry: Capitalizing on the Psychedelic Renaissance

Minsu Yoo, Sofia Sakopoulos

The commercialization of psychedelics like psilocybin, LSD, and MDMA for mental health treatment blurs the line between impartial science and profit-driven industry. Based on in-depth interviews with stakeholders, the study reveals how venture capitalists not only fund research but also provide regulatory and industry knowledge, creating ethical dilemmas for scientists. Researchers' reluctance to disclose personal psychedelic experiences during interviews signals a shift from an illegality paradigm to one of intellectual property. The findings suggest that ethical dynamics in scientific practice must be reconsidered, particularly how public and private funders shape researchers' priorities.

Psychedelics and autobiographical memory – Six open questions

Samuli Kangaslampi, Morten P. Lietz preprint

Psychedelics have long been thought to enhance autobiographical memory, and revisiting such memories may be key to their therapeutic effects, yet modern research has largely overlooked this area. This review identifies six open questions: whether psychedelics boost autobiographical recall; whether recalling significant or traumatic memories is common during psychedelic experiences; whether they can produce false memories; how memories change when recalled and reconsolidated under psychedelics; what memories of the psychedelic experience itself are like; and whether autobiographical experiences under psychedelics are especially important for therapeutic outcomes. The authors present the limited current evidence for each question and propose how future studies could address them, emphasizing relevance for optimizing psychedelic-assisted therapies and avoiding harm.

Psychedelics Use and the Risk of Reduced Formal Mental Health Care

Research Square • Sean Viña

People who use psychedelics are less likely to seek formal mental health care, including medication and outpatient treatment, even when experiencing high psychological distress. Analyzing data from over 458,000 participants in a national US survey between 2010 and 2018, the study found that as distress levels increase, psychedelic users become even less inclined to use formal care compared to non-users. This suggests a heightened risk of self-medication as psychedelics become more culturally and legally accepted.

Meditation, Psychedelics, and Brain Connectivity: A Randomised Controlled Resting-State fMRI Study of N,N -Dimethyltryptamine and Harmine in a Meditation Retreat

medRxiv • Klemens Egger, Daniel Meling, Firuze Polat et al. preprint

In a double-blind, placebo-controlled pharmaco-fMRI study, 40 meditation practitioners on a three-day retreat received either placebo or buccal DMT-harmine (120 mg each). Meditation alone increased network segregation across several resting-state networks, while DMT-harmine increased functional connectivity within the visual network and between visual and attention networks. Between-group differences showed increased connectivity between visual and salience networks in the DMT-harmine group. No prolonged cortical gradient disruption was observed, indicating a return to typical brain organization shortly after the experience. Meditation reduced connectivity between networks, whereas DMT-harmine increased within- and between-network connectivity, revealing distinct neural mechanisms.

Mindfulness-Based Psilocybin-Assisted Therapy (MB-PAT) for cancer-related demoralization in Canada: the case for a hybrid group-based delivery model

Christopher P. Albertyn, Jeremie Richard, Ron Joseph Shore et al. preprint

Demoralization syndrome affects about one in five Canadians with advanced cancer, marked by helplessness, hopelessness, and loss of meaning, and is linked to a greater desire for hastened death and worse outcomes, but it is underrecognized and undertreated. Pharmacological treatments fail to address its existential roots, and psychosocial therapies are underfunded and not universally effective. Mindfulness-Based Psilocybin-Assisted Therapy (MB-PAT) combines mindfulness training with psilocybin's neuroplastic effects, but its traditional one-on-one delivery limits scalability. The authors argue that group-based MB-PAT could bridge this gap by leveraging existing group therapy infrastructure and therapist familiarity with mindfulness, offering a scalable, equity-focused model for publicly funded Canadian oncology. The Canadian Network for Psychedelic-Assisted Cancer Therapy (CAN-PACT) is highlighted as a key initiative to generate evidence and capacity.

Case series of psilocybin self-medication for spinal cord injury

SSRN Electronic Journal • Robin Sandell, Adele Lafrance, Olivia Gosseries et al.

In three people with incomplete spinal cord injuries who self-medicated with psilocybin, improvements in motor function, muscle activation, and strength were reported. One person with a C4–C5 injury noted better gait automaticity; another with a T7 injury regained activation of a previously non-responsive hamstring muscle; a third with a T12 injury experienced rapid strength gains and enhanced proprioceptive awareness. All three reported psychological benefits such as increased wellbeing, motivation for recovery, and improved adjustment. Benefits appeared greatest in partially innervated muscles and diminished after stopping psilocybin. Temporary spasticity was the only adverse effect. The authors suggest psilocybin may enhance recovery by amplifying existing neural pathways and call for controlled clinical trials.

Regulating Psilocybin as Food, Not Drugs

Julia Etkin, Vincent Joralemon

Psilocybin, currently a Schedule I controlled substance with no accepted medical use and high abuse potential, is actually among the safest psychoactive compounds by comparative-harm metrics—far safer than alcohol and tobacco, which are exempt from the Controlled Substances Act and regulated as adult-use commodities. This essay argues that psilocybin should be regulated under food law, specifically the dietary-supplement framework of the Dietary Supplement Health and Education Act of 1994, rather than drug law.

Accurate and Interpretable Prediction of Antidepressant Treatment Response from Receptor-informed Neuroimaging

bioRxiv (Cold Spring Harbor Laboratory) • Hanna M. Tolle, Andrea I Luppi, Timothy Lawn et al. • 1 citation preprint

A geometric deep learning model called graphTRIP predicts post-treatment depression severity from pretreatment clinical and brain imaging data. Trained on a clinical trial comparing psilocybin and escitalopram, it achieves strong predictive accuracy (r = 0.75) and generalizes to an independent dataset. The model links better outcomes to reduced functional coupling within serotonin systems and broader serotonergic integration with sensory-motor networks. Causal analysis shows a group-level advantage of psilocybin over escitalopram but identifies individuals with specific stress-related neuromodulatory profiles who may benefit more from escitalopram, advancing precision medicine and biomarker discovery in depression.

Changes in anxiety, quality of life, and functioning following psilocybin-assisted therapy in veterans with treatment-resistant depression.

Journal of affective disorders • November 1, 2026 • Carlton M Kelly, Mathieu Fradet, Catherine M Bostian et al.

A single 25-mg dose of psilocybin with psychological support was associated with sustained improvements in anxiety, quality of life, functioning, and PTSD symptoms in 15 veterans with treatment-resistant depression. Anxiety scores dropped 59% from baseline at three weeks and remained lower through 12 months. Quality of life increased 24% and functional impairment decreased 46% at three weeks, though these effects were no longer statistically significant after accounting for concurrent improvements in depression. PTSD symptom reductions were observed at all timepoints. Acute subjective experiences did not correlate with treatment response. The study is limited by its small sample and open-label design.

Clinical trials

All Psilocybin trials →