Direct Comparison of Altered States of Consciousness Induced by LSD, Psilocybin, and DMT in Healthy Participants

Phase 1RecruitingNCT06899334

University Hospital, Basel, Switzerland24 enrolled

Overview

The primary objective of this study is to determine whether equivalent moderately high doses of LSD, psilocybin, and DMT produce qualitatively similar peak effects when the effect duration is standardized with ketanserin. A DMT infusion mimicking oral LSD and psilocybin administrations will be tested, as well as intravenously administered ketanserin.

Lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT) are serotonergic hallucinogens (psychedelics) and currently investigated as therapeutic tools for the treatment of various psychiatric disorders. They are usually administered in a dose range which induces an alteration of consciousness via the stimulation of the serotonin (5-HT)2A receptor. However, there are differences in the receptor activation profiles between the three substances that may induce different subjective effects. Moreover, they exhibit different pharmacokinetic qualities. In comparative studies of LSD and psilocybin blinding was impaired by the different duration of subjective effects. This study aims to ensure blinding by ending all experiences at the same time with the 5HT2A antagonist ketanserin. Moreover, no study has yet directly compared DMT to LSD and psilocybin. The DMT infusion will be modeled in accordance with the course of an oral LSD and psilocybin administration. Therefore, the LPD-study compares the acute and subacute effects of LSD, psilocybin, and DMT while standardizing the time course and the duration of action for all substances.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Enrollment

Conditions

Healthy

Interventions

LSDDRUG

A moderate to high oral dose of 150 µg LSD will be administered followed by 20 mg intravenous ketanserin after 3 h

PsilocybinDRUG

A moderate to high oral dose of 30 mg psilocybin will be administered followed by 20 mg intravenous ketanserin after 3 h

DMTDRUG

A moderate to high, dose-escalating, intravenous infusion up to 2 mg/min DMT will be administered followed by 20 mg intravenous ketanserin after 3 h

Eligibility

Sex: ALLMin age: 25 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: 1. Good understanding of the German language 2. Understanding of procedures and risks associated with the study 3. Willing to adhere to the protocol and signing of the consent form 4. Willing to refrain from the consumption of illicit psychoactive substances during the study 5. Willing not to operate heavy machinery within 48 h after administration of a study substance 6. Willing to use effective birth control throughout study participation 7. Body mass index 17 - 34.9 kg/m2 Exclusion Criteria: 1. Relevant chronic or acute medical condition 2. Current or previous major psychiatric disorder (e.g. psychotic disorder) 3. Psychotic disorder or bipolar disorder in first-degree relatives 4. Hypertension (SBP\>140/90 mmHg) or hypotension (SBP\<85 mmHg) 5. Bradycardia (\< 45 bpm) 6. Prolonged QTc interval (males: \>450 ms, females: \>470 ms) 7. AV block II° (Mobitz type and Webckebach type) and III° 8. Hallucinogenic substance use (not including cannabis) more than 20 times or any time within the previous two months 9. Pregnancy or current breastfeeding 10. Participation in another clinical trial (currently or within the last 30 days) 11. Use of medication that may interfere with the effects of the study medication 12. Tobacco smoking (\>10 cigarettes/day) 13. Excessive consumption of alcoholic beverages (\>15 drinks/week)

Locations (1)

University Hospital

Basel, Switzerland

RECRUITING

Outcomes

Primary Outcomes

1. Altered state of consciousness profile (5D-ASC)

5 Dimensions of Altered States of Consciousness (5D-ASC) consisting of 94 items to be rated on a visual analog scale (0-100 mm), with higher values indicating stronger effects.

Time frame: 18 months

Secondary Outcomes

Subjective effects (VASs)

Visual Analog Scales assessing the intensity and duration of subjective effects on a scale from 0 - 100 percent with higher scores representing more intense effects.

Time frame: 18 months

Mystical-type experiences (PES)

This 100-item Psychedelic Experience Questionnaire/Scale (PES100) is rated on a six-point scale (0 indicating "not at all" and 5 indicatin "extremely"). It comprises distractor items as well as subscales which measure mystical-type effects.

Time frame: 18 months

Mystical-type experiences (PAE-PS-ext)

This Phenomenological-Autobiographical-Existential Psychedelic Scale extended (PAE-PS-ext) questionnaire rates psychedelic experiences with a focus on phenomenological, autobiographical, and existential psychedelic experiences (scale from 0 - 100 percent with higher scores representing more intense effects).

Time frame: 18 months

3. Emotional breakthrough inventory (EBI+)

This 18-item questionnaire is a visual analog scale (from 0 - 100 percent with higher scores representing more intense effects) assessing emotional breakthrough throughout the study sessions.

Time frame: 18 months

Plasma levels of LSD

Assessed 20 times on each study day via blood samples

Time frame: 18 months

Central Contacts

Matthias E Liechti, Prof. Dr. MD

CONTACT

61 328 68 68 matthias.liechti@usb.ch

Mélusine Humbert-Droz, MSc

CONTACT

61 328 48 19 melusine.humbert-droz@usb.ch

Data from ClinicalTrials.gov

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