HealthyEarly Phase 1LDRNCT03321136
Role of the Serotonin 5-HT2A Receptor in LSD-induced Altered States of Consciousness (LDR-Study)
A Early Phase 1 study testing LSD in people with Healthy, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
Trial summary
Serotonin receptors, especially the 5HT2A receptor, are thought to be involved in the effects of various recreationally used psychedelic substances such as LSD. LSD potently stimulates the 5-HT2A receptor but also 5-HT2B/C, 5-HT1 and dopaminergic receptors. Read more about this study
- Who is it for?
- Ages 25 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- LSD
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 16 participants
- Where
- 1 siteSwitzerland
- Study dates
- 28 Nov 2017to 11 Jul 2019
- Phase
- Early Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age between 25 and 65 years.
- Understanding of the German language.
- Understanding the procedures and the risks 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.
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- 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.
Who cannot join
- 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)
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- 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)
Trial locations and contacts
1 site in 1 country.
About this study
Serotonin receptors, especially the 5HT2A receptor, are thought to be involved in the effects of various recreationally used psychedelic substances such as LSD. LSD potently stimulates the 5-HT2A receptor but also 5-HT2B/C, 5-HT1 and dopaminergic receptors. LSD induces acute transient alterations in waking consciousness including visual perceptual alterations, audio-visual synesthesia, derealization and depersonalization. LSD has therefore been used as experimental tool ("psychotomimetic") in modern psychiatric research to study psychotic-like states and model psychosis in healthy subjects [1-5]. However, the dose-effects of 5-HT2A receptor stimulation by LSD has not yet been studied. Additionally, there is still very limited data to what extent the 5HT2A receptor contributes to LSD's effects and its role in the mediation of the full response to LSD at a high dose is unclear. A recent experimental human study showed the 5-HT2A receptor antagonist ketanserin fully blocked the subjective effects of a moderate dose of 100 µg of LSD [6]. But, whether the effects of a high 200 µg oral dose of LSD can be blocked by the selective pharmacological 5-HT2A antagonist ketanserin remains to be tested to confirm the critical role of the 5-HT2A receptor in more pronounced alterations of consciousness and perception. The present study therefore explores the role the 5-HT2A receptor in LSD-induced altered states of consciousness using escalating doses of LSD and the 5-HT2A receptor blocker ketanserin administered before a high dose of LSD.
- Conditions
- Healthy
- Being tested
- LSD, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LSDDrug
Also called Lysergic Acid Diethylamide
0.025 mg LSD per os, single dose
LSDDrug
Also called Lysergic Acid Diethylamide
0.05 mg LSD per os, single dose
LSDDrug
Also called Lysergic Acid Diethylamide
0.1 mg LSD per os, single dose
LSDDrug
Also called Lysergic Acid Diethylamide
0.2 mg LSD per os, single dose
LSDDrug
Also called Lysergic Acid Diethylamide
0.2 mg LSD plus 40 mg ketanserin per os, single doses each
PlaceboDrug
Capsules containing mannitol looking identical to the other drugs.
| Study group | Role | What they receive |
|---|---|---|
| Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin | Placebo comparator | Cross-over within-subjects design with all treatment conditions, separated by a wash-out phase Receives: Drug: LSD; Drug: Placebo |
| LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo | Placebo comparator | Cross-over within-subjects design with all treatment conditions, separated by a wash-out phase Receives: Drug: LSD; Drug: Placebo |
| LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25 | Placebo comparator | Cross-over within-subjects design with all treatment conditions, separated by a wash-out phase Receives: Drug: LSD; Drug: Placebo |
| LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50 | Placebo comparator | Cross-over within-subjects design with all treatment conditions, separated by a wash-out phase Receives: Drug: LSD; Drug: Placebo |
| LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100 | Placebo comparator | Cross-over within-subjects design with all treatment conditions, separated by a wash-out phase Receives: Drug: LSD; Drug: Placebo |
| LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200 | Placebo comparator | Cross-over within-subjects design with all treatment conditions, separated by a wash-out phase Receives: Drug: LSD; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Altered states of consciousness
total 5D-ASC score (5-Dimensional Altered States of Consciousness Rating Scale)
Measured: 18 months
Secondary outcomes (8)
Subjective effects
VAS (Visual analog scales)
Measured: 18 months
Subjective effects
AMRS scales (Adjective mood rating scale)
Measured: 18 months
Psychotomimetic effects
ESI scale (Eppendorf Schizophrenia Inventory)
Measured: 18 months
Mystical-type experiences
MS scales (Mysticism scale)
Measured: 18 months
Mystical-type experiences
SCQ scales (States of consciousness questionnaire)
Measured: 18 months
Autonomic effects
Blood pressure
Measured: 18 months
Autonomic effects
Heart Rate
Measured: 18 months
Autonomic effects
Body temperature
Measured: 18 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Oct 2017
- Study start28 Nov 2017
- Primary completion5 Jul 2019
- Study completion11 Jul 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by University Hospital, Basel, SwitzerlandThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 16 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Matthias E Liechti, MD, MAS, Principal investigator, University Hospital, Basel, Switzerland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03321136
- Sponsor's protocol ID
- BASEC-2017-01348
- Acronym
- LDR
- Status last verified
- Aug 2019
- First submitted
- 8 Sep 2017
- Last updated
- 28 Aug 2019
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 Aug 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Role of the Serotonin 5-HT2A Receptor in LSD-induced Altered States of Consciousness (LDR-Study)
- ClinicalTrials.gov ID
- NCT03321136
- Acronym / sponsor ID
- LDR / BASEC-2017-01348
- Conditions
- Healthy
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 16 participants (actual)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Study start
- 28 Nov 2017 (actual)
- Primary completion
- 5 Jul 2019 (actual)
- Study completion
- 11 Jul 2019 (actual)
- First posted
- 25 Oct 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Serotonin receptors, especially the 5HT2A receptor, are thought to be involved in the effects of various recreationally used psychedelic substances such as LSD. LSD potently stimulates the 5-HT2A receptor but also 5-HT2B/C, 5-HT1 and dopaminergic receptors. LSD induces acute transient alterations in waking consciousness including visual perceptual alterations, audio-visual synesthesia, derealization and depersonalization. LSD has therefore been used as experimental tool ("psychotomimetic") in modern psychiatric research to study psychotic-like states and model psychosis in healthy subjects [1-5]. However, the dose-effects of 5-HT2A receptor stimulation by LSD has not yet been studied. Additionally, there is still very limited data to what extent the 5HT2A receptor contributes to LSD's effects and its role in the mediation of the full response to LSD at a high dose is unclear. A recent experimental human study showed the 5-HT2A receptor antagonist ketanserin fully blocked the subjective effects of a moderate dose of 100 µg of LSD [6]. But, whether the effects of a high 200 µg oral dose of LSD can be blocked by the selective pharmacological 5-HT2A antagonist ketanserin remains to be tested to confirm the critical role of the 5-HT2A receptor in more pronounced alterations of consciousness and perception. The present study therefore explores the role the 5-HT2A receptor in LSD-induced altered states of consciousness using escalating doses of LSD and the 5-HT2A receptor blocker ketanserin administered before a high dose of LSD.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 6
| Arm | Type | Receives |
|---|---|---|
| Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin | Placebo comparator | Drug: LSD, Drug: PlaceboCross-over within-subjects design with all treatment conditions, separated by a wash-out phase |
| LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo | Placebo comparator | Drug: LSD, Drug: PlaceboCross-over within-subjects design with all treatment conditions, separated by a wash-out phase |
| LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25 | Placebo comparator | Drug: LSD, Drug: PlaceboCross-over within-subjects design with all treatment conditions, separated by a wash-out phase |
| LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50 | Placebo comparator | Drug: LSD, Drug: PlaceboCross-over within-subjects design with all treatment conditions, separated by a wash-out phase |
| LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100 | Placebo comparator | Drug: LSD, Drug: PlaceboCross-over within-subjects design with all treatment conditions, separated by a wash-out phase |
| LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200 | Placebo comparator | Drug: LSD, Drug: PlaceboCross-over within-subjects design with all treatment conditions, separated by a wash-out phase |
Who may qualify
- Ages
- 25 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- Age between 25 and 65 years.
- Understanding of the German language.
- Understanding the procedures and the risks 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.
Key exclusion criteria (9 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LSDAlso: Lysergic Acid Diethylamide0.025 mg LSD per os, single dose | Drug | LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin |
| LSDAlso: Lysergic Acid Diethylamide0.05 mg LSD per os, single dose | Drug | LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin |
| LSDAlso: Lysergic Acid Diethylamide0.1 mg LSD per os, single dose | Drug | LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin |
| LSDAlso: Lysergic Acid Diethylamide0.2 mg LSD per os, single dose | Drug | LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin |
| LSDAlso: Lysergic Acid Diethylamide0.2 mg LSD plus 40 mg ketanserin per os, single doses each | Drug | LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin |
| PlaceboCapsules containing mannitol looking identical to the other drugs. | Drug | LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200-Ketanserin, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin, Placebo, LSD-25, Placebo, LSD-25, LSD-50, LSD-100, LSD-200, LSD-200-Ketanserin |
Primary outcome
Altered states of consciousness
Time frame: 18 months
total 5D-ASC score (5-Dimensional Altered States of Consciousness Rating Scale)
8 secondary outcomes
Subjective effects
Time frame: 18 months
Subjective effects
Time frame: 18 months
Psychotomimetic effects
Time frame: 18 months
Mystical-type experiences
Time frame: 18 months
Mystical-type experiences
Time frame: 18 months
Autonomic effects
Time frame: 18 months
Autonomic effects
Time frame: 18 months
Autonomic effects
Time frame: 18 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Aug 2019.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Matthias E Liechti, MD, MAS principal investigator
University Hospital, Basel, Switzerland
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing LSD in people with Healthy, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Aug 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Altered states of consciousness (time frame: 18 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Aug 2019.