Drug: Psilocybine

What It Is

Psilocybin is the compound in the mushrooms sometimes called magic mushrooms. The body converts it to psilocin. Psilocin switches on a serotonin receptor (5-HT2A) and produces a temporary, dose-dependent shift in perception, mood, and sense of self that lasts a few hours. In research it is the most studied of the classic psychedelics, ahead of LSD and DMT. The trial evidence is strongest for two uses: depression, including depression that has not responded to standard treatment, and the depression and anxiety that come with a life-threatening illness. Every one of those trials shared the same setting: a screened patient, a prepared session with trained support, and structured follow-up afterward. That setting is part of the treatment, a different situation from taking a substance alone.

What It Does

The largest controlled trial to date gave a single 25 mg dose, paired with psychological support, to people whose depression had not responded to standard treatment. Depression scores fell 6.6 points more than a group given a 1 mg comparison dose at three weeks, on the MADRS scale (0 to 60). A 10 mg dose did not separate from the comparison. The three-week gain had faded by twelve weeks, and side effects such as headache, nausea, and low mood were common.

A separate trial tested psilocybin directly against escitalopram, a standard antidepressant. At six weeks the two did not differ significantly. The gap was 2.0 points on the QIDS-SR-16, and the confidence interval crossed zero. Some secondary measures leaned toward psilocybin, but the trial was not large enough to settle them. The claim that gets repeated, that psilocybin outperformed an antidepressant, is not what the primary outcome showed.

In people facing a life-threatening cancer, the evidence is more consistent. Two randomized crossover trials each gave a single moderate-to-high dose with psychological support. Both produced immediate, large reductions in depression and anxiety alongside a greater sense of meaning. About 60 to 80 percent of participants still showed a meaningful improvement roughly six months later. Both trials were small. In a crossover design, most people could tell which session was active.

Psilocybin produces unmistakable effects, so almost everyone in a trial can tell whether they got the drug. A systematic review found this functional unblinding is pervasive: participants and raters correctly told the drug from the placebo more than 90 percent of the time. When people know they received a treatment they hoped would work, expectation can lift their scores. That expectation is hard to separate from the drug itself.

It means the measured size of the benefit is likely inflated, and the true size of the drug effect is not yet established.

For decades the received view held that psilocybin was a dangerous drug of no medical value, a stance written into law in the early 1970s. The trial evidence no longer supports that view. As attention grew, a second belief took hold, that it sits close to a cure. The data sit between the two: a real, repeatable short-term signal in depression and end-of-life distress, measured through weak blinding.

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

Mood & stress

One 25 mg psilocybin dose eased treatment-resistant depression 6.6 points more than a low dose at three weeksEmerging

In plain terms

A single high dose of psilocybin, given with therapy, eased treatment-resistant depression more than a tiny comparison dose after three weeks. The improvement had faded by twelve weeks, and side effects were common.

In detail

The phase 2b COMP360 trial (Goodwin et al., NEJM 2022) randomized 233 adults with treatment-resistant depression to a single 25 mg, 10 mg, or 1 mg dose of synthetic psilocybin with psychological support. On the MADRS scale (0 to 60), the 25 mg group improved 6.6 points more than the 1 mg comparator at week 3, while the 10 mg group did not separate from it. The between-group difference was no longer statistically significant at week 12. Adverse events, including headache, nausea, and low mood, occurred in most participants, and suicidal ideation and self-injurious behavior were reported across dose groups.

The study · 1

Goodwin et al., single-dose psilocybin for a treatment-resistant episode of major depression · N Engl J Med 2022;387:1637-1648

Psilocybin did not clearly beat a standard antidepressant on the main depression measure at six weeksEmerging · no effect

In plain terms

When psilocybin was tested head-to-head against a standard antidepressant, the two came out about even on the main measure of depression. Some secondary measures leaned toward psilocybin, but the study was too small to decide.

In detail

Carhart-Harris et al. (NEJM 2021) randomized 59 adults with moderate-to-severe depression to two doses of psilocybin with support, or to six weeks of daily escitalopram plus two very low psilocybin doses. On the primary outcome, the change in QIDS-SR-16 score at six weeks, the between-group difference was -2.0 points favoring psilocybin (95% CI -5.0 to 0.9, P=0.17), which was not statistically significant. Several secondary outcomes favored psilocybin, but the trial was not designed or powered to confirm them.

The study · 1

Carhart-Harris et al., trial of psilocybin versus escitalopram for depression · N Engl J Med 2021;384:1402-1411

A single psilocybin session eased cancer-related distress, with 60 to 80% still improved at about six monthsEmerging

In plain terms

For people facing life-threatening cancer, a single psilocybin session with support eased depression and anxiety, and most were still better roughly six months later.

In detail

A Johns Hopkins crossover trial (Griffiths et al. 2016, 51 patients) and an NYU crossover trial (Ross et al. 2016, 29 patients) each gave people with cancer-related depression and anxiety a single moderate-to-high psilocybin dose with psychological support, compared with a very low dose or an active control. Both produced immediate, substantial, and sustained decreases in depressed mood and anxiety alongside increases in quality of life and sense of meaning; at roughly six months, 60 to 80% of participants still showed clinically significant improvement.

The studies · 2

Griffiths et al., psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer · J Psychopharmacol 2016;30:1181-1197

Ross et al., rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer · J Psychopharmacol 2016;30:1165-1180

Evidence And Methods

Participants and raters correctly guess who got psilocybin more than 90% of the time, so the benefit is hard to separate from expectationEmerging · mixed

In plain terms

Because psilocybin produces obvious effects, people in the studies can usually tell whether they got the active drug, which makes the benefit hard to separate from expectation.

In detail

Une revue systématique de l'intégrité de l'insu dans les essais randomisés sur les psychédéliques (Orsini et al. 2026) a constaté que seule une minorité d'essais évaluait l'insu, alors que plus de la moitié le mentionnaient comme une limite. Là où il était mesuré, la levée fonctionnelle de l'insu était substantielle : les études sur la psilocybine rapportaient fréquemment que les participants et les évaluateurs devinaient correctement l'attribution dans plus de 90 pour cent des cas. Cela ne montre pas que les traitements sont sans effet ; cela montre que la taille d'effet mesurée ne peut pas être fermement attribuée au médicament tant que l'insu reste aussi faible.

The study · 1

Orsini et al., blinding integrity in psychedelic randomized clinical trials, a systematic review · JAMA Psychiatry 2026

How it works

La psilocybine agit via son métabolite, la psilocine, sur le récepteur sérotoninergique 5-HT2AEmerging · mixed

In plain terms

Le corps transforme la psilocybine en psilocine, qui active un récepteur de la sérotonine (5-HT2A). Ce seul récepteur serait à l'origine de l'expérience, et on pense qu'il assouplit les schémas de pensée figés.

In detail

Des revues pharmacologiques complètes (Nichols 2016) établissent que les effets subjectifs des psychédéliques classiques dépendent de l'agonisme au récepteur sérotoninergique 5-HT2A : bloquer ce récepteur bloque l'expérience. La psilocybine elle-même est largement inactive et est déphosphorylée en psilocine, l'agoniste actif. L'activation est censée augmenter la flexibilité de l'activité corticale et réduire l'emprise d'une pensée rigide et autoréférentielle, un mécanisme d'intérêt pour la dépression et la détresse en fin de vie.

The study · 1

Nichols et al., psychedelics, a comprehensive pharmacology review · Pharmacol Rev 2016;68:264-355

How It Works

The effects of psilocybin turn on one mechanism. The body converts it to psilocin, and psilocin activates the serotonin 5-HT2A receptor. Block that single receptor and the experience disappears. That is how researchers know it is central. Activating it appears to raise the flexibility of activity across the cortex and to loosen the fixed, self-referential thinking common in depression and rumination. The therapeutic idea: a well-supported person revisits thoughts, memories, and feelings from a new vantage point, and that shift can outlast the few hours the drug is active.

What Happens During and After a Session

1The receptor and the acute effect

Psilocin switches on the serotonin 5-HT2A receptor across the cortex. Over the following minutes to hours this changes perception, emotion, and the sense of self. In the studied setting the person is prepared, supported by trained staff, and kept in a calm room. Those conditions matter most as the dose rises.

2The days after

The subjective experience ends within hours, but many trials report a change in mood that appears over the following days. In treatment-resistant depression this early separation from the comparison dose was clear at three weeks. The mechanism proposed for a lasting shift, a temporary window of greater mental flexibility, is still being worked out, and mechanism alone does not establish clinical benefit.

3Weeks to months

The depression signal in the largest trial had faded by twelve weeks, which is why the compound is studied with structured follow-up rather than as a single event. In the cancer trials the benefit held longer, with most people still improved around six months. How durable the effect is, and for whom, is one of the open questions the research has not settled.

The Legal Position

The law has not caught up with the science. As of 2026, in the United States:

• Psilocybin is Schedule I federally, the most restricted category, so outside an authorized research or approved-treatment setting its use is illegal.
• Oregon and Colorado have created state-regulated frameworks for supervised adult psilocybin use, legal under state law but not under the federal classification.
• It has not been approved by the FDA for any condition, so a doctor cannot prescribe it.

Elsewhere it stays investigational, reachable only inside clinical trials and expanded-access programs.

Go Deeper

• Psychedelics in mental health: the wider picture, where psilocybin sits beside MDMA-assisted therapy for PTSD and the approved relative esketamine. It covers the 2024 FDA decision and the blinding problem that runs across the whole field.
• Depression: what actually helps: the full range of treatments, and where an investigational option like psilocybin sits among the ones with a longer track record.
• Anxiety: the condition that runs alongside much of this research, and the treatments with the strongest evidence behind them.

The Chinese Medicine View

Chinese medicine has a long-standing frame for altered states of mind, and it leans toward caution. The Heart is said to house the Shen, the spirit or consciousness. Clear thought, steady emotion, and restful sleep are read as signs of a settled Shen. A mind flooded, disoriented, or thrown into fear or agitation is described as a disturbance of the Shen. The classical tradition treats such disturbance as something to calm and anchor. The bias of the medicine runs toward grounding. It settles the Shen, harmonizes Heart and Liver, and roots a scattered mind back in the body through stillness, breath, and regular life.

Read through that lens, an intense mind-altering experience could be seen as deliberately stirring the Shen. The tradition would approach that with great care, most of all when the person is already depleted, agitated, or unsettled, or when skilled support and a calm setting are missing. The classical texts predate modern trials, and the parallel here is a later reading. It lines up, in its own language, with what the clinical evidence keeps showing: the fragile person is the one most likely to be harmed. The wider preventive tradition of Yang Sheng, nourishing life, would place grounding practices first.

Cautions For This Practice

Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.

Les psychédéliques ont déclenché une manie chez 5.8 % à 30 % des personnes et peuvent provoquer une psychose chez les personnes vulnérables

La méta-analyse (Eskinazi et al. 2026) a regroupé des essais contrôlés et des études naturalistes. Les taux d'hypomanie ou de manie allaient de 5.8 % dans les essais contrôlés de thérapie assistée par psilocybine pour la dépression jusqu'à 30 % dans l'usage naturaliste chez des personnes présentant des troubles du spectre bipolaire. Une revue narrative distincte sur les psychédéliques et les troubles du spectre de la schizophrénie (Brar et al. 2026) conclut qu'ils peuvent déclencher une psychose chez des individus vulnérables, tout en notant que l'ampleur de ce risque est mal quantifiée. C'est pourquoi les essais excluent les antécédents personnels ou familiaux de trouble bipolaire ou de psychose.Eskinazi et al., psychedelic-induced hypomania and mania, a systematic review and meta-analysisBrar et al., the intersection between psychedelics and schizophrenia spectrum disorders, reevaluating risk and therapeutic potential

En usage non supervisé, 11 % des personnes se remémorant une expérience difficile se sont mises elles-mêmes ou ont mis autrui en danger de préjudice physique

Une enquête en ligne (Carbonaro et al. 2016) a interrogé des personnes (78 % d'hommes, âge moyen d'environ 30 ans) sur l'expérience psychologiquement la plus difficile de leur vie avec des champignons à psilocybine. Onze pour cent ont rapporté s'être mises elles-mêmes ou avoir mis autrui en danger de préjudice physique, 2.6 % ont eu un comportement agressif, et 2.7 % ont cherché une aide médicale ; parmi celles dont l'expérience remontait à plus d'un an, 7.6 % avaient cherché un traitement pour des symptômes persistants. La difficulté, la dose, et l'absence de confort physique et de soutien social augmentaient toutes la probabilité de risque. Malgré la difficulté, 84 % ont tout de même rapporté avoir bénéficié de l'expérience dans l'ensemble.Carbonaro et al., survey study of challenging experiences after ingesting psilocybin mushrooms

Le mélange d'un psychédélique classique avec le lithium a provoqué des crises convulsives dans 47 % des cas rapportés

Des chercheurs (Nayak et al. 2021) ont analysé des témoignages autodéclarés en ligne combinant un psychédélique classique et un stabilisateur de l'humeur. Sur 62 témoignages lithium plus psychédélique, 47 % impliquaient des crises convulsives, 18 % supplémentaires impliquaient un mauvais trip, et 39 % nécessitaient une prise en charge médicale ; sur 34 témoignages lamotrigine plus psychédélique, aucun n'impliquait de crises convulsives. Les auteurs concluent que cette combinaison pourrait présenter un risque significatif de crises convulsives pour les personnes prenant du lithium.Nayak et al., classic psychedelic coadministration with lithium, but not lamotrigine, is associated with seizures

This is not a guide to using psilocybin

This page is education about the research, the law, and the risks. It carries no dosing, no sourcing, and no instructions for use. Use outside an approved-treatment or research setting is illegal in most places, and unsupervised use carries psychological and medical risk. The trial results come from screened patients in prepared sessions with trained support, which is a very different situation from taking a substance alone.

Bipolar disorder and a history of psychosis

A personal or family history of bipolar disorder or of psychosis is the most important reason for caution. A meta-analysis found rates of psychedelic-linked hypomania or mania ranging from about 5.8% in controlled psilocybin depression trials to 30% in naturalistic use by people with bipolar spectrum conditions, and reviews note that psychedelics can provoke psychosis in vulnerable people. This is why trials screen these histories out.

Serotonergic medicines and lithium

Serotonin-based antidepressants (SSRIs and SNRIs) can blunt the effect of psilocybin, and combining serotonergic drugs raises the concern of too much serotonin. Combining a classic psychedelic with lithium has been linked to seizures in a large share of reported cases. Anyone on psychiatric medication is in a situation where these interactions can be dangerous, and a prescribing clinician is the right person to consult before any change.

Set, setting, and supervision

The research points repeatedly to the same thing: preparation, a calm and safe environment, and skilled support shape how an experience goes. In the survey evidence, difficulty and the risk of harm rose at higher doses and when support and physical comfort were absent. The phrase the field uses is set, setting, and supervision, and it separates the studied conditions from unsupervised use.

Psilocybin is the most studied classic psychedelic, and its benefit, though real, does not hold for long. Its risks depend heavily on the person, the dose, and the setting, and anything touching your own care or medication is a question for a prescribing clinician.

Common Questions

Does psilocybin work for depression?

Half a century after psilocybin was pulled from medicine, the depression evidence is only now being built back, and what it shows is real but short-lived. A doctor still cannot prescribe it in 2026, so the label is investigational.

Can I get psilocybin as a treatment?

Not as an approved treatment in 2026: the FDA has not approved it, so no doctor can prescribe it. A mental-health clinician can lay out the treatments that already exist, and check your eligibility for an active trial. A trial is the main lawful route to the drug itself, outside the two states that regulate supervised adult use.

Why is the evidence described as uncertain if the trials were positive?

A positive trial result is not the same as a proven drug once the blind breaks. The blinding here was weak, so better-designed studies are what would settle it.

Who should be especially careful?

The trials handle this by screening. Each one interviews candidates first and turns some away, because psilocybin is safe for most people but hazardous for a few. The interview is where a personal or family psychiatric history, and every current medication, gets weighed. Take that same history and medication list to any clinician before going near a 5-HT2A drug.