Clinical TrialHealthy VolunteersLSDPsilocybinDMTPlaceboRecruiting

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

This randomised, placebo-controlled, triple-blind Phase I crossover trial (n=24) will compare the acute and subacute effects of LSD (150µg), psilocybin (30mg), and DMT (up to 2 mg/min intravenous infusion) in healthy adults, with all sessions standardised using ketanserin (20 mg IV) to end the psychedelic experience after three hours.

Target Enrollment
24 participants
Study Type
Phase I interventional
Design
Randomized, triple Blind

Detailed Description

The LPD study is a 4-period randomized crossover in healthy volunteers to compare moderately high doses of LSD (150 µg), psilocybin (30 mg) and an IV DMT infusion (modeled to match oral kinetics) while standardising experience duration using 20 mg IV ketanserin at three hours.

Primary aims are basic science: to assess whether equivalent peak subjective effects occur across compounds when duration is fixed; outcomes include acute and subacute subjective measures and pharmacokinetic/pharmacodynamic characterisation.

Study Protocol

Preparation

sessions

Dosing

4 sessions
180 min each

Integration

sessions

Study Arms & Interventions

LSD

experimental

150 µg oral LSD followed by 20 mg IV ketanserin at 3 h; part of 4-period randomized crossover.

Interventions

  • LSD150 µg
    via Oral• single dose• 1 doses total

    150 µg oral LSD

  • Compound20 mg
    via IV• single dose• 1 doses total

    Ketanserin 20 mg IV administered at 3 h to terminate experience

Psilocybin

experimental

30 mg oral psilocybin followed by 20 mg IV ketanserin at 3 h; part of 4-period randomized crossover.

Interventions

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

    30 mg oral psilocybin

  • Compound20 mg
    via IV• single dose• 1 doses total

    Ketanserin 20 mg IV administered at 3 h to terminate experience

DMT

experimental

Dose-escalating IV DMT infusion (modeled to match oral LSD/psilocybin time-course) up to 2 mg/min, followed by 20 mg IV ketanserin at 3 h; part of 4-period randomized crossover.

Interventions

  • DMT2 mg/min
    via IV• infusion• 1 doses total

    Dose-escalating IV infusion up to 2 mg/min to mimic oral time-course

  • Compound20 mg
    via IV• single dose• 1 doses total

    Ketanserin 20 mg IV administered at 3 h to terminate experience

Placebo

inactive

Oral and IV placebo followed by 20 mg IV ketanserin at 3 h; part of 4-period randomized crossover.

Interventions

  • Placebo
    via Oral• single dose• 1 doses total

    Oral and IV placebo as control

  • Compound20 mg
    via IV• single dose• 1 doses total

    Ketanserin 20 mg IV administered at 3 h in placebo condition as per protocol

Participants

Ages
25 – 99
Sexes
Male & Female

Inclusion Criteria

  • Inclusion Criteria:\n\n1. Good understanding of the German language\n2. Understanding of procedures and risks associated with the study\n3. Willing to adhere to the protocol and signing of the consent form\n4. Willing to refrain from the consumption of illicit psychoactive substances during the study\n5. Willing not to operate heavy machinery within 48 h after administration of a study substance\n6. Willing to use effective birth control throughout study participation\n7. Body mass index 17 - 34.9 kg/m2

Exclusion Criteria

  • Exclusion Criteria:\n\n1. Relevant chronic or acute medical condition\n2. Current or previous major psychiatric disorder (e.g. psychotic disorder)\n3. Psychotic disorder or bipolar disorder in first-degree relatives\n4. Hypertension (SBP>140/90 mmHg) or hypotension (SBP<85 mmHg)\n5. Bradycardia (< 45 bpm)\n6. Prolonged QTc interval (males: >450 ms, females: >470 ms)\n7. AV block II° (Mobitz type and Webckebach type) and III°\n8. Hallucinogenic substance use (not including cannabis) more than 20 times or any time within the previous two months\n9. Pregnancy or current breastfeeding\n10. Participation in another clinical trial (currently or within the last 30 days)\n11. Use of medication that may interfere with the effects of the study medication\n12. Tobacco smoking (>10 cigarettes/day)\n13. Excessive consumption of alcoholic beverages (>15 drinks/week)

Study Details

Locations

University Hospital — Basel, Switzerland

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