NCT04227756: LPM

Comparative Acute Effects of LSD, Psilocybin and Mescaline

Completed Phase 1 Last updated 24 January 2024

What this trial tests

Phase 1 trial testing LSD in Healthy in 32 participants. Completed in 2 September 2022.

Timeline

19 May 2020

Primary endpoint
2 September 2022

2 September 2022

Quick facts

Lead sponsor	University Hospital, Basel, Switzerland
Phase	Phase 1
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	crossover
Masking	quadruple
Primary purpose	basic science
Enrollment	32
Start date	19 May 2020
Primary completion	2 September 2022
Estimated completion	2 September 2022
Sites	1 location across Switzerland

Drugs / interventions tested

• LSD — full drug profile →
• Psilocybin — full drug profile →
• Mescaline — full drug profile →
• Placebo

Conditions studied

• Healthy — all drugs for Healthy →

Sponsor

University Hospital, Basel, Switzerland

Who can join

Adults 25 to 65, any sex, with Healthy. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

LSD, psilocybin and mescaline are widely used for recreational and ethnomedical purposes. All three substances are thought to induce prototypical psychedelic effects primarily via stimulation of the 5-HT2A receptor. However, there are differences in the substances' molecular structures and receptor activation profiles which may induce differential subjective effects. To date, there are no modern studies comparing LSD, psilocybin and mescaline directly within the same clinical study and research subjects using validated psychometric tools. Therefore, the LPM-Study compares the acute effects of LSD, psilocybin, mescaline and placebo in a double-blind, placebo-controlled, 4-period cross-over design with four treatment conditions: 1) 100 μg LSD, 2) 20 mg psilocybin, 3) 300 or 500 mg mescaline, and 4) placebo.

Publications & conference data

8 peer-reviewed publications reference this trial (live from Europe PMC):

1. Adverse effects of psychedelics: From anecdotes and misinformation to systematic science.
   Schlag AK, Aday J, Salam I, Neill JC, et al · · 2022 · cited 170× · PMID 35107059 · DOI 10.1177/02698811211069100
2. Comparative acute effects of mescaline, lysergic acid diethylamide, and psilocybin in a randomized, double-blind, placebo-controlled cross-over study in healthy participants.
   Ley L, Holze F, Arikci D, Becker AM, et al · · 2023 · cited 91× · PMID 37231080 · DOI 10.1038/s41386-023-01607-2
3. Adverse experiences resulting in emergency medical treatment seeking following the use of magic mushrooms.
   Kopra EI, Ferris JA, Winstock AR, Young AH, et al · · 2022 · cited 42× · PMID 35388724 · DOI 10.1177/02698811221084063
4. <i>In vitro</i> and <i>in vivo</i> metabolism of psilocybin's active metabolite psilocin.
   Thomann J, Kolaczynska KE, Stoeckmann OV, Rudin D, et al · · 2024 · cited 32× · PMID 38741590 · DOI 10.3389/fphar.2024.1391689
5. Pharmacological and non-pharmacological predictors of the LSD experience in healthy participants.
   Vizeli P, Studerus E, Holze F, Schmid Y, et al · · 2024 · cited 9× · PMID 39231959 · DOI 10.1038/s41398-024-03074-9
6. Safety pharmacology of acute psilocybin administration in healthy participants.
   Straumann I, Holze F, Becker AM, Ley L, et al · · 2024 · cited 6× · PMID 40656108 · DOI 10.1016/j.nsa.2024.104060
7. Classic Psychedelics in Pain Modulation: Mechanisms, Clinical Evidence, and Future Perspectives.
   Czopek A, Jończyk J, Fryc M, Kluzik D, et al · · 2025 · cited 3× · PMID 40474592 · DOI 10.1021/acschemneuro.5c00152
8. An Overview on the Hallucinogenic Peyote and Its Alkaloid Mescaline: The Importance of Context, Ceremony and Culture.
   Doesburg-van Kleffens M, Zimmermann-Klemd AM, Gründemann C. · · 2023 · cited 1× · PMID 38138432 · DOI 10.3390/molecules28247942