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Psilocybin for depression: what the trials found

Trials show psilocybin with psychological support can cut depression scores within days, but the evidence is early and one large trial missed its goal.

Published October 2026

Short answer

In supervised trials, psilocybin with therapy eased depression quickly, and benefits sometimes lasted months. The evidence is early: trials are small, blinding is nearly impossible, and a large 2026 trial missed its main goal. Evidence grade C (Limited). Multiple meta-analyses of small randomised trials found medium-to-large symptom improvements, but people can usually tell whether they received the real dose (all trials at risk of bias), pooled samples are under about 500, and a large 2026 trial missed its primary end point; downgraded from A for each of these.

Key takeaways

  • In pooled analyses of randomised trials, psilocybin-assisted therapy reduced depression scores by a medium-to-large margin compared with placebo or very low doses [1][2].
  • One 104-person trial found depression scores fell about 12 points more than placebo by day 43, with effects visible within 8 days [3].
  • A triple-blinded trial of 144 people missed its primary response end point, though secondary measures favoured psilocybin [4].
  • Common side effects - headache, nausea, dizziness and brief anxiety - usually settle within 48 hours; serious events are uncommon but reported [5][6].
  • Psilocybin is studied only with psychological support and supervision, and remains illegal in many countries outside trials [7].

The short version

Psilocybin, the compound in magic mushrooms, is being tested as a treatment for depression in clinical trials, and several reviews have now pooled the results [8][1]. In studies it is given as a single high dose under supervision, with psychological support before, during and after the session [9]. Pooled results show medium-to-large drops in depression scores compared with placebo or very low doses [1][2]. The evidence is still limited: most trials are small, people can usually tell whether they received the real dose, and a large, triple-blinded 2026 trial missed its primary end point [4].

What the studies show

A 2024 BMJ review pooled seven randomised trials (436 people) and found psilocybin cut depression scores more than placebo or non-psychoactive controls, with a medium-to-large effect (Hedges' g 0.66; 95% CI 0.46 to 0.86) [1]. A 2025 review of six trials found a similar short-term effect (standardised mean difference -0.72 across five pooled trials, 403 people) and higher response and remission rates than comparison groups [2].

The biggest early trial gave 233 people with treatment-resistant depression one supervised dose of 25 mg, 10 mg or 1 mg. The 25 mg dose lowered MADRS depression scores by 12.0 points at week 3 versus 5.4 for 1 mg; 10 mg did not clearly beat 1 mg, and the advantage was no longer significant at 12 weeks [9]. In a 104-person trial, a single 25 mg dose lowered MADRS scores by 12.3 points more than a niacin placebo by day 43 - and by 12.0 points by day 8 - alongside better everyday functioning [3].

Two smaller 2026 trials found benefits too: an NHS feasibility trial (60 people) reported MADRS scores 10.4 points better than placebo at week 3 [10], and a 35-person trial found effects from day 2 to day 42 that had faded by the one-year follow-up [11]. Not every trial agrees: a 59-person trial found no significant difference from the antidepressant escitalopram on the primary measure, though remission was higher with psilocybin (57% vs 28%, a secondary result) [12]. The 144-person EPISODE trial set out to blind participants, investigators and raters, and found response rates of 17.0% with 25 mg versus 10.6% with an active placebo - not statistically significant - while secondary depression measures did favour psilocybin [4].

In people with a life-threatening illness, a 2024 Cochrane review of five small trials (122 people) found psilocybin-type psychedelics may ease anxiety and depression, with low-certainty evidence [7]. For alcohol use disorder, a 95-person trial found heavy drinking days fell to 9.7% from 23.6% over 32 weeks [13], but a later 37-person trial found no significant difference in drinking outcomes [14].

The nuances

Most trials enrolled adults with moderate-to-severe or treatment-resistant depression and excluded people with psychosis or mania histories, active substance use disorder or serious suicidal intent, so the results do not describe everyone [3]. Treatment always includes psychological support and medical supervision [7], and dosing is nothing like "microdosing": trials used single high doses, mostly 25 mg [9], while three small placebo-controlled trials of repeated tiny doses found no improvement in mood or wellbeing [15][16][17].

Safety: the most common short-term effects are headache, nausea, dizziness, brief anxiety and a temporary rise in blood pressure, usually settling within 48 hours [5]. Serious events are uncommon - about 4% of participants with existing psychiatric conditions in one review of 114 studies [6] - but manic or hypomanic symptoms have been reported, mostly briefly, in people with bipolar vulnerability (5.8% in controlled trials, up to 30% in observational studies) [18]. One large trial reported more suicidal ideation during dosing days (4% vs 1-2%) and a single case of lasting visual disturbance [4]. Psilocybin can interact with psychiatric medicines, including antidepressants [19], and it remains illegal in many countries outside approved research [7].

What this means for you

Psilocybin for depression is a supervised clinical treatment, not something trials support doing at home: every study gave it with preparatory and follow-up therapy, in a medical setting [7]. The results are encouraging for a treatment that can work within days [3], but they are early: bigger trials with better blinding are still needed to show how it compares with standard antidepressants and who benefits most [4]. People who want to try it can ask a doctor about clinical trials; outside studies it remains illegal in many places [7].

Go deeper

  • Psilocybin — In supervised trials, psilocybin-assisted therapy reduces depression symptoms quickly, with effects often lasting weeks to months.

References

  1. Efficacy of psilocybin for treating symptoms of depression: systematic review and meta-analysis.. BMJ, 2024.
  2. Randomized Controlled Trials of Psilocybin-Assisted Therapy in the Treatment of Major Depressive Disorder: Systematic Review and Meta-Analysis.. Acta Psychiatr Scand, 2025.
  3. Single-Dose Psilocybin Treatment for Major Depressive Disorder: A Randomized Clinical Trial.. JAMA, 2023.
  4. Efficacy and Safety of Psilocybin in Treatment-Resistant Major Depression: The EPISODE Randomized Clinical Trial.. JAMA Psychiatry, 2026.
  5. Acute Adverse Effects of Therapeutic Doses of Psilocybin: A Systematic Review and Meta-Analysis.. JAMA Netw Open, 2024.
  6. Adverse Events in Studies of Classic Psychedelics: A Systematic Review and Meta-Analysis.. JAMA Psychiatry, 2024.
  7. Psychedelic-assisted therapy for treating anxiety, depression, and existential distress in people with life-threatening diseases.. Cochrane Database Syst Rev, 2024.
  8. Breaking the chains of depression: A systematic review and meta-analysis of psilocybin therapy.. J Affect Disord, 2026.
  9. Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression.. N Engl J Med, 2022.
  10. Psilocybin-assisted therapy for treatment-resistant major depressive disorder in a public healthcare setting: a randomized controlled trial.. Nat Med, 2026.
  11. Short-Term and Late-Term Effects of Psilocybin on Symptoms in Major Depression: A Randomized Clinical Trial.. JAMA Netw Open, 2026.
  12. Trial of Psilocybin versus Escitalopram for Depression.. N Engl J Med, 2021.
  13. Percentage of Heavy Drinking Days Following Psilocybin-Assisted Psychotherapy vs Placebo in the Treatment of Adult Patients With Alcohol Use Disorder: A Randomized Clinical Trial.. JAMA Psychiatry, 2022.
  14. Psilocybin-assisted therapy for relapse prevention in alcohol use disorder: a phase 2 randomized clinical trial.. EClinicalMedicine, 2025.
  15. Microdosing with psilocybin mushrooms: a double-blind placebo-controlled study.. Transl Psychiatry, 2022.
  16. Psilocybin microdosing does not affect emotion-related symptoms and processing: A preregistered field and lab-based study.. J Psychopharmacol, 2022.
  17. Cognitive and subjective effects of psilocybin microdosing: Results from two double-blind placebo-controlled longitudinal trials.. Neuropharmacology, 2026.
  18. Psychedelic-induced hypomania and mania: a systematic review and meta-analysis.. Mol Psychiatry, 2026.
  19. Drug-drug interactions between psychiatric medications and MDMA or psilocybin: a systematic review.. Psychopharmacology (Berl), 2022.