Clinical TrialHealthy VolunteersLSDLSDPsilocybinPsilocybinPlaceboCompleted

Direct Comparison of Altered States of Consciousness Induced by LSD and Psilocybin

The investigators will compare the acute effects of LSD, psilocybin and placebo.

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

Detailed Description

Randomised, quadruple-blind, within-subject crossover in healthy volunteers (n=28) comparing single oral doses of LSD (0.1 mg, 0.2 mg), psilocybin (15 mg, 30 mg) and placebo with washout between sessions.

Aims are to directly compare subjective altered states and related brain measures (functional imaging) and to explore receptor-profile differences between LSD and psilocybin for basic neuroscience purposes.

Study Protocol

Preparation

sessions

Dosing

5 sessions

Integration

sessions

Study Arms & Interventions

LSD 100

experimental

Oral LSD 0.1 mg single-dose; crossover within-subjects

Interventions

  • LSD0.1 mg
    via Oral• single dose• 1 doses total

LSD 200

experimental

Oral LSD 0.2 mg single-dose; crossover within-subjects

Interventions

  • LSD0.2 mg
    via Oral• single dose• 1 doses total

Psilocybin 15

experimental

Oral psilocybin 15 mg single-dose; crossover within-subjects

Interventions

  • Psilocybin15 mg
    via Oral• single dose• 1 doses total

Psilocybin 30

experimental

Oral psilocybin 30 mg single-dose; crossover within-subjects

Interventions

  • Psilocybin30 mg
    via Oral• single dose• 1 doses total

Placebo

inactive

Oral placebo single-dose; crossover within-subjects

Interventions

  • Placebo
    via Oral• single dose• 1 doses total

Participants

Ages
25 – 65
Sexes
Male & Female

Inclusion Criteria

  • Inclusion Criteria:
  • 1. Age between 25 and 65 years.
  • 2. Understanding of the German language.
  • 3. Understanding the procedures and the risks that are associated with the study.
  • 4. Participants must be willing to adhere to the protocol and sign the consent form.
  • 5. Participants must be willing to refrain from taking illicit psychoactive substances during the study.
  • 6. Participants must be willing to drink only alcohol-free liquids and no coffee, black or green tea, or energy drink after midnight of the evening before the study session, as well as during the study day.
  • 7. Participants must be willing not to drive a traffic vehicle or to operate machines within 48 h after substance administration.
  • 8. Women of childbearing potential must have a negative pregnancy test at the beginning of the study. Pregnancy tests are repeated before each study session.
  • 9. Women of childbearing potential must be willing to use double-barrier birth control
  • 10. Body mass index 18-29 kg/m2.

Exclusion Criteria

  • Exclusion Criteria:
  • 1. Chronic or acute medical condition
  • 2. Current or previous major psychiatric disorder
  • 3. Psychotic disorder in first-degree relatives
  • 4. Illicit substance use (with the exception of cannabis) more than 10 times or any time within the previous two months.
  • 5. Pregnant or nursing women.
  • 6. Participation in another clinical trial (currently or within the last 30 days)
  • 7. Use of medications that may interfere with the effects of the study medications (any psychiatric medications)
  • 8. Tobacco smoking (>10 cigarettes/day)
  • 9. Consumption of alcoholic drinks (>10/week)
  • 10. Bodyweight < 50 kg

Study Details

Locations

Clinical Pharmacology & Toxicology, University Hospital Basel — Basel, Switzerland

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