NCT03604744

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

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

• Status: Completed
• Phase: EARLY_Phase 1
• Study type: Interventional
• Enrollment: 28 (actual)
• Sponsor: University Hospital, Basel, Switzerland · Academic / Other
• Sex: All
• Age: 25 Years – 65 Years
• Healthy volunteers: Accepted

Summary

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.

Conditions

• Healthy

Interventions

Type	Name	Description
DRUG	LSD	LSD 0.1 mg per os, single dose
DRUG	LSD	LSD 0.2 mg per os, single dose
DRUG	Psilocybin	Psilocybin 15 mg per os, single dose
DRUG	Psilocybin	Psilocybin 30 mg per os, single dose

Timeline

• Start date: 2019-03-27
• Primary completion: 2021-04-10
• Completion: 2021-04-15
• First posted: 2018-07-27
• Last updated: 2021-04-27

Locations

1 site across 1 country: Switzerland