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Recruiting NCT06796361

Role of the Serotonin 2A Receptor in Psilocybin-induced Altered States of Consciousness

Phase I Interventional Healthy

For patients and families

In plain language

An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.

What is being studied
The protocol lists: Ketanserin 40mg plus Psilocybin 40mg, 40mg Psilocybin, 20mg Psilocybin, 10mg Psilocybin.
Who it may be relevant to
Registry conditions: Healthy. Basic parameters: 25 years — 75 years · All.
What needs checking
Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
Where it takes place
Switzerland
Next step
Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →

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Official title

Role of the Serotonin 2A Receptor in Psilocybin-induced Altered States of Consciousness (PDR-Study)

Overview

Psilocybin (active compound of "magic mushrooms") is a prototypical psychedelic substance that acts via agonism on serotonin (5-HT) 2A receptors. Psilocybin is rapidly metabolized into its active metabolite psilocin. Psilocybin is currently under investigation as potential treatment for various neuropsychiatric disorders. Psilocybin is also widely used for recreational purposes and as research tool in neuroscience. Besides its current clinical development, a clear characterization of the dose-response relationship of psilocybin is lacking. With the present study the investigators aim to close this knowledge gap by administering low (5mg) to high (40mg) single doses of psilocybin to healthy participants. Besides its agonism on 5-HT2A receptors, psilocin also binds to other receptors and inhibits serotonin transporters (SERT). To this data only few studies have investigated these effects and never at a high dose.

Detailed description

Psilocybin is widely used for recreational and spiritual purposes. Additionally Psilocybin is currently reused in experimental studies with healthy subjects and in studies investigating its effects on patients suffering from anxiety, depression, addiction personality disorders and other pathological conditions.

The present PDR-study will characterize the subjective effects of different doses of psilocybin using modern psychometric instruments, explore the relationship between the plasma-concentration of psilocybin and its subjective effects, and examine the contribution of the 5-HT2A receptor in the psilocybin-induced alterations of consciousness in a mechanistic study in healthy subjects.

Participants will recieve doses of 5, 10, 20, and 40 mg psilocybin, 40 mg of psilocybin with pretreatment of 40 mg ketanserin, and placebo (control for psilocybin). Placebo pretreatment (control for ketanserin) will be used for all psilocybin administrations without ketanserin. Administrations will be separated by at least 10 days and are in random and counter-balanced order.

Interventions

  • Drug Ketanserin 40mg plus Psilocybin 40mg
    40mg Ketanserin oral will be administered followed by 40mg Psilocybin.
  • Drug 40mg Psilocybin
    Placebo oral followed by 40mg Psilocybin one hour later.
  • Drug 20mg Psilocybin
    Placebo oral followed by 20mg Psilocybin one hour later.
  • Drug 10mg Psilocybin
    Placebo oral followed by 10mg Psilocybin oral one hour later.
  • Drug 5mg Psilocybin
    Placebo oral followed by 5mg Psilocybin one hour later
  • Other Placebo
    Oral Placebo followed by oral Placebo one hour later

Primary outcome measures

  • 5 dimensions of altered state of consciousness (5D-ASC) total OAV score [Time frame: 10 hours after substance administration]
Secondary outcome measures (12)
  • Visual Analog Scales (VAS) good effect rating [Time frame: One hour before, right after and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10 and 24 hours after substance administration]
  • Adjective Mood Rating Scale AMRS [Time frame: One hour before as well as 3, 6, 10 and 24 hours after substance administration]
  • States of consciousness questionnaire (SCQ) [Time frame: 10 hours after substance administration]
  • Phenomenological-Autobiographical-Existential Psychedelic Scale extended (PAE-PS-ext) [Time frame: This questionnaire is administrated once before the first substance day (during screening), and then again 10h after substance administration on everx study visit..]
  • Acute autonomic effects I (blood pressure) [Time frame: One hour before, right after and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10 and 24 hours after substance administration]
  • Acute autonomic effects II (heart rate) [Time frame: One hour before, right after and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10 and 24 hours after substance administration]
  • Acute autonomic effects III (body temperature) [Time frame: One hour before, right after and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10 and 24 hours after substance administration]
  • Effect moderation by personality traits I (NEO-FFI) [Time frame: Screening]
  • Effect moderation by personality traits II (FPI-R) [Time frame: Screening]
  • Effect moderation by personality traits III (SPF) [Time frame: Screening]
  • Effect moderation by personality traits IV (HEXACO) [Time frame: Screening]
  • Effect moderation by personality traits V (DSQ-40) [Time frame: Screening]

Eligibility criteria

Inclusion criteria

  • Age between 25 and 75 years.
  • Sufficient 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 (not including cannabis).
  • 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 be willing to use effective birth-control throughout study participation

Exclusion criteria

  • Chronic or acute medical condition, including a history of seizures.
  • Body mass index 18-29.9 kg/m2
  • Current or previous major psychiatric disorder (e.g. psychotic disorders, mania / hypomania, anxiety disorders).
  • Psychotic or bipolar disorder in first-degree relatives, not including psychotic disorders secondary to an apparent medical reason, e.g., brain injury, dementia, or lesions of the brain.
  • Hypertension (SBP>140/90 mmHg) or hypotension (SBP<85 mmHg)
  • Psychedelic substance use (with the exception of cannabis) more than 20 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 and any medication with known to interact with the study substances).
  • Tobacco smoking (>10 cigarettes/day).
  • Consumption of alcoholic drinks (>15 drinks / week).
  • Body weight < 45 kg.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation
Randomized
Model
Crossover
Masking
Triple blind
Primary purpose
Basic science

Study locations

Switzerland · 1 center
  • Clinical Trial Unit — Basel

Identifiers

NCT: NCT06796361 · BASEC 2024-01503 · BASEC 2024-01503

Primary sources (government registries)

View this study on ClinicalTrials.gov ↗