Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: similarities and differences in subjective experiences.
Theresa M. Carbonaro, Matthew W Johnson, Ethan Hurwitz, Roland R. Griffiths
Psychopharmacology February 1, 2018 DOI: 10.1007/s00213-017-4769-4 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Double-blind Peer reviewed |
|---|---|
| Sample size | 20 |
| Population | Healthy participants with histories of hallucinogen use |
| Interventions | Psilocybin Dextromethorphan |
| Dose | 10, 20, 30 mg/70 kg for psilocybin; 400 mg/70 kg for DXM |
| Duration | Single acute dose, no follow-up reported |
| Topics | Mystical experience Psilocybin |
| Keywords | Dextromethorphan Hallucinogen Humans Psychedelic Double-blind comparison Powerful subjective experience Uniquely fosters Richer Profound insightful experience Music absorption More complex journey Disembodiment |
| Citations | 139 |
| Key findings | Psilocybin produced significantly greater visual, mystical-type, insightful, and musical experiences than DXM, while DXM produced greater disembodiment. |
Abstract
Although psilocybin and dextromethorphan (DXM) are hallucinogens, they have different receptor mechanisms of action and have not been directly compared. This study compared subjective, behavioral, and physiological effects of psilocybin and dextromethorphan under conditions that minimized expectancy effects. Single, acute oral doses of psilocybin (10, 20, 30 mg/70 kg), DXM (400 mg/70 kg), and placebo were administered under double-blind conditions to 20 healthy participants with histories of hallucinogen use. Instructions to participants and staff minimized expectancy effects. Various subjective, behavioral, and physiological effects were assessed after drug administration. High doses of both drugs produced similar increases in participant ratings of peak overall drug effect strength, with similar times to maximal effect and time-course. Psilocybin produced orderly dose-related increases on most participant-rated subjective measures previously shown sensitive to hallucinogens. DXM produced increases on most of these same measures. However, the high dose of psilocybin produced significantly greater and more diverse visual effects than DXM including greater movement and more frequent, brighter, distinctive, and complex (including textured and kaleidoscopic) images and visions. Compared to DXM, psilocybin also produced significantly greater mystical-type and psychologically insightful experiences and greater absorption in music. In contrast, DXM produced larger effects than psilocybin on measures of disembodiment, nausea/emesis, and light-headedness. Both drugs increased systolic blood pressure, heart rate, and pupil dilation and decreased psychomotor performance and balance. Psilocybin and DXM produced similar profiles of subjective experiences, with psilocybin producing relatively greater visual, mystical-type, insightful, and musical experiences, and DXM producing greater disembodiment.
Comparable studies
Other randomized controlled trials on psilocybin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial Cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety | 2016 | Randomized controlled trial | n = 51 |
| Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial Patients with cancer-related anxiety and depression | 2016 | Double-blind, placebo-controlled, crossover trial | n = 29 |
| Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance Hallucinogen-naïve adults reporting regular participation in religious or spiritual... | 2006 | Double-blind study | n = 36 |
| Trial of Psilocybin versus Escitalopram for Depression Selected group of patients with depression | 2021 | Randomized controlled trial | |
| Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder Adults aged 21 to 75 years with major depressive disorder, not currently using... | 2020 | Randomized controlled trial | n = 24 |
Citations in the library
Cited by 119
- REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics Pharmacological Reviews June 20, 2019
- Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function. Pharmacology & Therapeutics May 1, 2019
- Emotions and brain function are altered up to one month after a single high dose of psilocybin. Scientific Reports February 10, 2020
- Adverse effects of psychedelics: From anecdotes and misinformation to systematic science. Journal of Psychopharmacology February 2, 2022
- Brain entropy, fractal dimensions and predictability: A review of complexity measures for EEG in healthy and neuropsychiatric populations European Journal of Neuroscience August 19, 2022
and 114 more in the library
Cites 36
- Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance Psychopharmacology July 7, 2006
- Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology July 1, 2008
- Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action Neuroreport December 1, 1998
- Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects. Psychopharmacology December 1, 2011
- Psychometric Evaluation of the Altered States of Consciousness Rating Scale (OAV) PLoS One August 31, 2010
and 31 more in the library