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A comparison between psilocybin and esketamine in treatment-resistant depression using number needed to treat (NNT): A systematic review.

Sabrina Wong, Angela T H Kwan, Kayla M Teopiz, Gia Han Le, Shakila Meshkat, Roger Ho, Giacomo d'Andrea, Bing Cao, Joshua D. Di Vincenzo, Joshua D. Rosenblat, Roger S McIntyre

Journal of Affective Disorders April 1, 2024 DOI: 10.1016/j.jad.2024.01.142 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Systematic review Randomized Peer reviewed
Population Adults with treatment-resistant depression
Interventions Psilocybin Esketamine
Dose 25 mg psilocybin; 56 mg and 84 mg esketamine
Duration 21-day post-dose for psilocybin; 28-day post-dose for esketamine
Topics Depression Esketamine Psilocybin Psychedelic-assisted therapy
Keywords Antidepressant efficacy Mental health treatments Clinical outcomes
Citations 19
Key findings Both psilocybin (25 mg) and esketamine (56 mg and 84 mg) showed clinically meaningful NNT estimates and acceptable NNH profiles in adults with treatment-resistant depression.

Abstract

Inadequate outcomes with monoamine-based treatments in depressive disorders are common and provide the impetus for mechanistically-novel treatments. Esketamine is a proven treatment recently approved for adults with Treatment-Resistant Depression (TRD) while psilocybin is an investigational treatment. Translation of the clinical meaningfulness for these foregoing agents in adults with TRD is required. Herein we evaluate the Number Needed to Treat (NNT) and Harm (NNH) of esketamine and psilocybin in adults with TRD. We conducted a systematic review of randomized controlled trials, comparing the clinical efficacy of oral psilocybin to the co-commencement of intranasal esketamine with an oral antidepressant in adults with TRD. 25 mg psilocybin had a significant reduction in depressive symptoms at 21-days post-dose, the NNT was 5 [95 % CI = 3.1, 18.5]. Psilocybin-induced nausea had a significant NNH = 5. Fixed-dosed esketamine at 56 mg and 84 mg had a significant effect at 28-days post-dose, (NNT of 7 [95 % CI56mg = 3.5, 46.7], [95 % CI84mg = 3.6, 142.2]). Esketamine-induced headache, nausea, dizziness, and dissociation had NNHs <10. The preliminary results may only reflect a small portion of the patient population. These results require replication and longer term studies investigating maintenance therapy. Relatively few pharmacologic agents are proven safe and effective in adults with TRD. NNT estimates for investigational psilocybin and esketamine in TRD indicate clinical meaningfulness. The NNH profile for both aforementioned agents is clinically acceptable. Our results underscore the clinical relevance of these treatment options in adults with TRD.

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Comparable studies

Other systematic reviews and meta-analyses on ketamine and psychedelic-assisted therapy, most cited first.

Study Year Design Participants
Meta-correlation of the effect of ketamine and psilocybin induced subjective effects on therapeutic outcome. Patients with depression or substance use disorder 2024 Systematic review and meta-analysis n = 654
Ketamine and Ketamine-Assisted Psychotherapy for Psychiatric and Existential Distress in Patients with Serious Medical Illness: A Narrative Review. Patients with serious medical illness in a palliative care setting 2025 Systematic review
Psychedelic-Assisted Therapies for Psychosocial Symptoms in Cancer: A Systematic Review and Meta-Analysis Adults with cancer 2025 Systematic review and meta-analysis n = 455
How Do People Who Undergo Ketamine Treatment for a Psychiatric Problem Subjectively Experience This Intervention? A Meta-Synthesis of Qualitative Studies. People who received ketamine treatment for a psychiatric problem 2025 Systematic review and thematic meta-synthesis n = 24
Psychedelics and ketamine/esketamine in depressive disorders: biological mechanisms and associated neuroimaging and clinical changes. 2025 Systematic review

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