Current Understanding on Psilocybin for Major Depressive Disorder: A Review Focusing on Clinical Trials

Summary & key facts

This review looked at published clinical trials of psilocybin for depression. It found 11 trials (six open‑label and five double‑blind randomized trials) that report rapid antidepressant and anti‑anxiety effects in some patients. The paper describes how psilocybin acts on serotonin 5‑HT2A receptors, may boost brain plasticity, and may lower brain inflammation and default mode network activity, but it also says more research is needed on doses and long‑term effects.

Key facts:

• The authors identified 11 clinical trials of psilocybin for depression: six open‑label studies and five double‑blind randomized clinical trials (DB‑RCTs).
• The U.S. Food and Drug Administration designated psilocybin as a “breakthrough therapy” for treatment‑resistant depression in 2018.
• Psilocybin works mainly as an agonist at 5‑HT2A serotonin receptors and is described as a psychoplastogen that can increase glutamate transmission and factors like brain‑derived neurotrophic factor (BDNF).
• Clinical findings reported include: a pilot study in treatment‑resistant depression that showed significant symptom reductions after two psilocybin sessions.
• Two DB‑RCTs in cancer patients reported significant reductions in anxiety and depression that lasted for more than 6 months.
• In major depressive disorder (MDD), one DB‑RCT found psilocybin produced rapid reductions in depression and higher remission rates than escitalopram in that trial.
• A DB‑RCT in treatment‑resistant depression found a single 25 mg dose of psilocybin had a superior antidepressant effect compared with 1 mg, while a 10 mg dose did not show superiority over 1 mg.
• The review reports generally favorable safety profiles in the clinical trials but notes that optimal dosing and long‑term effects still need further study.

Abstract

Previous studies suggested effectiveness of psilocybin in the field of mental health. FDA designated psilocybin as a "breakthrough therapy" for the treatment of treatment-resistant depression (TRD) in 2018. This paper provided a review of psilocybin's potential role in treatment of depression by focusing on published clinical trials. Studies showed that psilocybin, an agonist on 5-HT2A receptors, manifests antidepressant and anxiolytic effects by increasing glutamate transmission, reducing brain inflammation, decreasing default mode network activity. In terms of clinical trials, eleven studies (six open-label and five double blinded randomized clinical trials [DB-RCTs]) trials exploring psilocybin's impact on depression were found. Among open-label studies, a pilot study on TRD patients demonstrated significant reductions in depressive symptoms after two psilocybin sessions. Psilocybin also improved cognitive bias associated with depression. Extension studies confirmed sustained improvements and high remission rates. Among five DB-RCTs, two showed that psilocybin led to significant reductions in anxiety and depression in cancer patients, and the improvements sustained for over six months. In MDD, psilocybin showed rapid reductions in depression, with higher remission rates compared to escitalopram in a DB-RCT. Another DB-RCT showed that psilocybin induced higher decrease in depression around 6 hours after their administrations than placebo. The last DB-RCT showed that in patients with TRD, a single dose of psilocybin 25 mg, but not psilocybin 10 mg, resulted in superior antidepressant effect than psilocybin 1 mg. Overall, psilocybin showed promise in treating depression and anxiety, with notable safety profiles. Further research should explore optimal dosages and long-term effects.

Topics

Mental Health Research Topics Psychedelics and Drug Studies Tryptophan and brain disorders

Categories

Clinical Psychology Psychology Social Sciences

Tags

Alternative medicine Antidepressant Anxiety Cognition Hallucinogen Internal medicine Major depressive disorder Medicine Pathology Pharmacology Placebo Psilocybin Psychiatry Psychology Randomized controlled trial Treatment-resistant depression