Psilocybin’s Potential Mechanisms in the Treatment of Depression: A Systematic Review
Harrison J Lee, Vivian Wl Tsang, Brandon S Chai, Michelle Cq Lin, Andrew Howard, Christopher Uy, Julius O Elefante
Journal of Psychoactive Drugs June 29, 2023 DOI: 10.1080/02791072.2023.2223195 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review Qualitative Peer reviewed |
|---|---|
| Population | Human and animal studies on psilocybin and depression |
| Topics | Depression Psilocybin |
| Keywords | Mechanism of action Psychedelic treatment Hallucinogenic medicine Antidepressant therapy Neuroscience brain chemistry Neural pathways Neurobiology |
| Citations | 19 |
| Key findings | Psilocybin's antidepressant mechanism likely involves multiple pathways, including changes in serotonin and glutamate receptor activity, synaptogenesis, and altered brain activity in the hippocampus and prefrontal cortex, but evidence on specific mechanisms remains sparse. |
Abstract
Evidence suggests that psilocybin has therapeutic benefit for treating depression. However, there is little consensus regarding the mechanism by which psilocybin elicits antidepressant effects. This systematic review summarizes existing evidence. Ovid MEDLINE, EMBASE, psychINFO, and Web of Science were searched, for both human and animal studies, using a combination of MeSH Terms and free-text keywords in September 2021. No other mood disorders or psychiatric diagnoses were included. Original papers in English were included. The PRISMA framework was followed for the screening of papers. Two researchers screened the retrieved articles from the literature search, and a third researcher resolved any conflicts. Of 2,193 papers identified, 49 were selected for full-text review. 14 articles were included in the qualitative synthesis. Six supported psilocybin's mechanism of antidepressant action via changes to serotonin or glutamate receptor activity and three papers found an increase in synaptogenesis. Thirteen papers investigated changes in non-receptor or pathway-specific brain activity. Five papers found changes in functional connectivity or neurotransmission, most commonly in the hippocampus or prefrontal cortex. Several neuroreceptors, neurotransmitters, and brain areas are thought to be involved in psilocybin's ability to mitigate depressive symptoms. Psilocybin appears to alter cerebral blood flow to the amygdala and prefrontal cortex, but the evidence on changes in functional connectivity and specific receptor activity remains sparse. The lack of consensus between studies suggests that psilocybin's mechanism of action may involve a variety of pathways, demonstrating the need for more studies on psilocybin's mechanism of action as an antidepressant.
Comparable studies
Other systematic reviews and meta-analyses on psilocybin for depression, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Therapeutic effects of classic serotonergic psychedelics: A systematic review of modern‐era clinical studies Patients with cancer- or illness-related anxiety and depression, major depressive... | 2020 | Systematic review | n = 188 |
| The experimental effects of psilocybin on symptoms of anxiety and depression: A meta-analysis People with elevated symptoms of anxiety and depression | 2020 | Meta-analysis | n = 117 |
| Psychedelics in the treatment of unipolar mood disorders: a systematic review Patients with broadly defined unipolar mood disorders | 2016 | Systematic review | n = 423 |
| Psychedelic therapy for depressive symptoms: A systematic review and meta-analysis. Participants in studies of psychedelic therapy for depressive symptoms (Major... | 2023 | Systematic review with meta-analysis | n = 14 |
| Serotonergic hallucinogens in the treatment of anxiety and depression in patients suffering from a life-threatening disease: A systematic review. Patients with life-threatening diseases and symptoms of anxiety or depression | 2018 | Systematic review | n = 445 |