Clinical TrialHealthy VolunteersLSDPsilocybinMescalinePlaceboCompleted

Comparative Acute Effects of LSD, Psilocybin and Mescaline

Double-blind, placebo-controlled, 4-period crossover study (n≈32) comparing single doses of LSD 100 µg, psilocybin 20 mg, mescaline 300/500 mg and placebo in healthy volunteers to characterise acute subjective, physiological and neural effects.

Target Enrollment
32 participants
Study Type
Phase I interventional
Design
Randomized, quadruple Blind

Detailed Description

The LPM study is a double-blind, placebo-controlled, four-period crossover in healthy volunteers comparing single oral doses of LSD (100 µg), psilocybin (20 mg), mescaline (300 or 500 mg) and placebo to determine whether these serotonergic hallucinogens produce qualitatively similar subjective alterations and brain activity patterns.

Outcomes include validated psychometric measures of subjective experience, physiological monitoring, and magnetic resonance imaging to investigate psychological, physiological and neuronal variables associated with acute psychedelic effects.

Study Protocol

Preparation

sessions

Dosing

4 sessions

Integration

sessions

Study Arms & Interventions

LSD-100

experimental

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

Interventions

  • LSD100 µg
    via Oral• single dose

    100 µg (0.1 mg)

Psilocybin-20

active comparator

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

Interventions

  • Psilocybin20 mg
    via Oral• single dose

Mescaline-300/500

active comparator

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

Interventions

  • Mescaline300 - 500 mg
    via Oral• single dose

    300 or 500 mg

Placebo

inactive

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

Interventions

  • Placebo
    via Oral• single dose

    Mannitol

Participants

Ages
25 – 65
Sexes
Male & Female

Inclusion Criteria

  • 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

  • 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

Study Details

Locations

University Hospital Basel, Clinical Trial Unit — Basel, Canton of Basel-City, Switzerland

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