Trial PaperDepressive DisordersMajor Depressive Disorder (MDD)Safety & Risk ManagementPsilocybin

Single-dose psilocybin-assisted therapy in major depressive disorder: A placebo-controlled, double-blind, randomised clinical trial

This double-blind placebo-controlled study (n=56) found that one psilocybin-assisted therapy (16mg/70kg, 2 prep + 3 integration meetings) session significantly reduced depressive symptoms (MADRS & BDI) in those suffering from a major depressive disorder (MDD, n=26). Fourteen days after the intervention, 54% of those in the psilocybin group met remission criteria (<10 on MADRS).

Authors

  • Erich Seifritz
  • Franz Vollenweider
  • Katrin Preller

Published

EClinicalMedicine
individual Study

Abstract

Background

Psilocybin has been suggested as a novel, rapid-acting treatment for depression. Two consecutive doses have been shown to markedly decrease symptom severity in an open-label setting or when compared to a waiting list group. To date, to our knowledge, no other trial compared a single, moderate dose of psilocybin to a placebo condition.

Methods

In this double-blind, randomised clinical trial, 52 participants diagnosed with major depressive disorder and no unstable somatic conditions were allocated to receive either a single, moderate dose (0.215 mg/kg body weight) of psilocybin or placebo in conjunction with psychological support. MADRS and BDI scores were assessed to estimate depression severity, while changes from baseline to 14 days after the intervention were defined as primary endpoints. The trial took place between April 11th, 2019 and October 12th, 2021 at the psychiatric university hospital in Zürich, Switzerland and was registered with clinicaltrials.gov (NCT03715127).

Findings

The psilocybin condition showed an absolute decrease in symptom severity of −13.0 points compared to baseline and were significantly larger than those in the placebo condition (95% CI −15.0 to −1.3; Cohens' d = 0.97; P = 0.0011; MADRS) and −13.2 points (95% CI; −13.4 to −1.3; Cohens’ d = 0.67; P = 0.019; BDI) 14 days after the intervention. 14/26 (54%) participants met the MADRS remission criteria in the psilocybin condition.

Interpretation

These results suggest that a single, moderate dose of psilocybin significantly reduces depressive symptoms compared to a placebo condition for at least two weeks. No serious adverse events were recorded. Larger, multi-centric trials with longer follow-up periods are needed to inform further optimisation of this novel treatment paradigm.

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Research Summary of 'Single-dose psilocybin-assisted therapy in major depressive disorder: A placebo-controlled, double-blind, randomised clinical trial'

Introduction

Interest in the therapeutic potential of psilocybin for major depressive disorder (MDD) has risen alongside recognition of limitations of current antidepressant treatments and reports of rapid, durable antidepressant responses following psilocybin administration. The authors note that many earlier studies suffered from small samples, open or waitlist comparators, likely functional unblinding of raters, and incomplete adverse event (AE) assessment, and that several larger trials have used short primary end points that leave questions about longer-term clinical utility in a chronic condition such as MDD. Raison and colleagues set out to address these gaps with a randomized, double-blind, multi-site Phase II trial comparing a single oral 25-mg dose of psilocybin to an active placebo (100-mg niacin) administered with standardised psychological support. The study aimed to characterise the timing, magnitude, durability (to six weeks), and safety of antidepressant effects while reducing rater unblinding through centralised remote assessments.

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Study Details

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