Skip to main content
OpenTrials
Completed

NCT Number: NCT03604744

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

LSD (lysergic acid diethylamide) and psilocybin (the active substance in "magic mushrooms") are widely used for recreational purposes. Both substances are also increasingly used in psychiatric and psychological research to induce and investigate alterations in waking consciousness and associated brain functions (functional brain imaging, "model psychosis") . However, it has never been studied whether there are differences in the alterations in mind produced by these two substances. Both LSD and psilocybin are thought to induce hallucinations primarily via stimulation of the 5-HT2A receptor. However, there are differences in the receptor activation profiles between the two substances that may also induce different subjective effects. LSD potently stimulates the 5-HT2A receptor but also 5-HT2B/C, 5-HT1 and D1-3 receptors . Psilocin (the active metabolite of the prodrug psilocybin) also stimulates the 5-HT2A receptor but additionally inhibits the 5-HT transporter. In contrast to LSD, psilocybin has no affinity for D2 receptors. Both substances are used in neuroscience as pharmacological tools. However, there are no modern studies comparing these two substances directly within the same clinical study and research subjects and using validated psychometric tools. Therefore, the investigators will compare the acute effects of LSD, psilocybin and placebo.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Healthy

Age range

25 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Early Phase 1

Primary location

Clinical Pharmacology & Toxicology, University Hospital Basel

Basel, 4056, Switzerland

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age between 25 and 65 years.
  • Understanding of the German language.
  • Understanding the procedures and the risks that are associated with the study.
  • Participants must be willing to adhere to the protocol and sign the consent form.
  • Participants must be willing to refrain from taking illicit psychoactive substances during the study.
  • 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.
  • Participants must be willing not to drive a traffic vehicle or to operate machines within 48 h after substance administration.
  • Women of childbearing potential must have a negative pregnancy test at the beginning of the study. Pregnancy tests are repeated before each study session.
  • Women of childbearing potential must be willing to use double-barrier birth control
  • Body mass index 18-29 kg/m2.

Exclusion criteria

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

Treatment and study plan

LSD

Drug

LSD 0.1 mg per os, single dose

Psilocybin

Drug

Psilocybin 15 mg per os, single dose

Primary outcomes

  1. Altered states of consciousness

    Time frame: 18 Months

    total 5D-ASC score (5-Dimensional Altered States of Consciousness Rating Scale)

Secondary outcomes

  1. Subjective effects assessed by VAS

    Time frame: 18 Months

    VAS (Visual analog scale)

  2. Subjective effects assessed by AMRS scales

    Time frame: 18 Months

    AMRS scales (Adjective mood Rating scale)

  3. Psychotomimetic effects

    Time frame: 18 Months

    ESI (Eppendorf Schizophrenia Inventory)

  4. Mystical-type experiences assessed by SCQ

    Time frame: 18 Months

    SCQ (States of consciousness questionnaire)

  5. Mystical-type experiences assessed by MS scales

    Time frame: 18 Months

    MS scales (Mysticism scale)

  6. Effects on emotion processing

    Time frame: 18 Months

    FERT (Face Emotion Recognition Task)

  7. Autonomic effects assessed by heart rate

    Time frame: 18 Months

    Heart rate

  8. Autonomic effects assessed by blood pressure

    Time frame: 18 Months

    Blood pressure (diastolic and systolic)

  9. Autonomic effects assessed by body temperature

    Time frame: 18 Months

    Body temperature

Other outcomes

  1. Plasma levels of LSD and psilocin

    Time frame: 18 Months

    assessment of plasma levels of LSD and psilocin

Sponsors and collaborators

Lead sponsor

University Hospital, Basel, Switzerland

Other

Registry information

Official study title

Direct Comparison of Altered States of Consciousness Induced by LSD and Psilocybin in a Random-order Placebo-controlled Cross-over Study in Healthy Subjects

Acronym: LSD-psilo

Important dates

Study start
2019
Primary completion
2021
Study completion
2021
First posted
Jul 27, 2018
Registry last updated
Apr 27, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.