Comparative Acute Effects of LSD, Psilocybin and Mescaline

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE1

Total Enrollment

32 participants

Study Classification

INTERVENTIONAL

Study Start Date

2020-05-19

Study Completion Date

2022-09-02

Brief Summary

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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.

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Detailed Description

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LSD (lysergic acid diethylamide), psilocybin (the active substance in "magic mushrooms") and mescaline (the active substance in Peyote and San Pedro cacti) are serotonergic hallucinogens widely used for recreational and/or ethnomedical purposes. LSD, psilocybin and mescaline are thought to induce prototypical psychedelic effects primarily via stimulation of the 5-HT2A receptor. However, there are differences in their molecular structures (LSD: ergoline, psilocybin: tryptamine; mescaline: phenethylamine)and receptor activation profiles which may induce different subjective effects. To date, there are no modern studies comparing these three substances 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. The main objective of this study is to determine whether LSD, psilocybin and mescaline produce qualitatively similar subjective alterations of mind and associated brain activity patterns despite their unique receptor activation profiles. The study investigates psychological (psychometry), physiological and neuronal (magnetic resonance imaging) variables. The LPM-Study provides insight into the acute effects profiles of three serotonergic hallucinogens. It will enhance the understanding of psychedelic-induced altered states of consciousness in humans and will be relevant for the fields of psychiatry, psychology, and forensic toxicology.

Conditions

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Healthy

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Double-blind, placebo-controlled, 4-period cross-over design with four treatment conditions

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors

Study Groups

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LSD-100

Cross-over within-subject design with all treatment conditions, separated by a wash-out phase of at least 10 days

Group Type EXPERIMENTAL

LSD

Intervention Type DRUG

LSD 0.1 mg per os, single dose OR Psilocybin 20 mg per os, single dose OR Mescaline 300 mg per os, single dose OR Placebo

Psilocybin-20

Cross-over within-subject design with all treatment conditions, separated by a wash-out phase of at least 10 days

Group Type ACTIVE_COMPARATOR

Psilocybin

Intervention Type DRUG

Psilocybin 20 mg per os, single dose

Mescaline-300/500

Cross-over within-subject design with all treatment conditions, separated by a wash-out phase of at least 10 days

Group Type ACTIVE_COMPARATOR

Mescaline

Intervention Type DRUG

Mescaline 300 mg or 500 mg per os, single dose

Placebo

Cross-over within-subject design with all treatment conditions, separated by a wash-out phase of at least 10 days

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type OTHER

Placebo (Mannitol)

Interventions

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LSD

LSD 0.1 mg per os, single dose OR Psilocybin 20 mg per os, single dose OR Mescaline 300 mg per os, single dose OR Placebo

Intervention Type DRUG

Psilocybin

Psilocybin 20 mg per os, single dose

Intervention Type DRUG

Mescaline

Mescaline 300 mg or 500 mg per os, single dose

Intervention Type DRUG

Placebo

Placebo (Mannitol)

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

1. Age between 25 and 65 years old
2. Sufficient understanding of the German language
3. Understanding of procedures and risks associated with the study
4. Willing to adhere to the protocol and signing of the consent form
5. Willing to refrain from the consumption of illicit psychoactive substances during the study
6. Abstaining from xanthine-based liquids from the evenings prior to the study sessions to the end of the study days
7. Willing not to operate heavy machinery within 48 hours after substance administration
8. Willing to use double-barrier birth control throughout study participation
9. Body mass index between 18-29 kg/m2

Exclusion Criteria

1. Chronic or acute medical condition
2. Current or previous major psychiatric disorder
3. Psychotic disorder or bipolar disorder in first-degree relatives
4. Hypertension (\>140/90 mmHg) or hypotension (SBP\<85 mmHg)
5. Hallucinogenic substance use (not including cannabis) more than 20 times or any time within the previous two months
6. Pregnancy or current breastfeeding
7. Participation in another clinical trial (currently or within the last 30 days)
8. Use of medication that may interfere with the effects of the study medication
9. Tobacco smoking (\>10 cigarettes/day)
10. Consumption of alcoholic beverages (\>20 drinks/week)
11. Failure of MRI-related criteria

Minimum Eligible Age

25 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes