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Neuropharmacological Investigation of Ayahuasca Constituents DMT and HarminePhase 1HaD-PETNCT06252506

Molecular Imaging Study of Harmine/DMT: a Basic Research Approach

A Phase 1 study testing N,N-dimethyltryptamine (DMT) + harmine in people with Neuropharmacological Investigation of Ayahuasca Constituents DMT and Harmine, run by Insel Gruppe AG, University Hospital Bern at 2 sites in Switzerland.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The few reports on effects of psychedelic substances on cerebral metabolic rate (CMRglc) indicate increases (psilocybin; human FDG-PET) or decreases (LSD, rat autoradiography; 5-MeO-DMT rat autoradiography). There are no reports of effects of DMT and/or harmine on cerebral energy metabolism. Read more about this study

Who is it for?
Ages 25 to 45 years, men onlyHealthy volunteers can take part
What is being tested?
N,N-dimethyltryptamine (DMT) + harmine
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
17 participants
Where
2 sitesSwitzerland
Study dates
22 Jan 2024to 5 Mar 2025
Phase
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 45 years
  • Men only
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Between 25-45 years old
  • Good command of the German language
  • Willing and capable to give consent for the participation in the study after it has been thoroughly explained
  • Willing and capable to comply with all study requirements
  • Body mass index (BMI) between 18.5 and 35
  • Previous experience with psychedelics, but not in the past three months
  • Willing to abstain from alcohol, caffeinated drinks, nicotine, food, and sugary drinks for two hours prior to the PET scan on the testing day, and from consuming psychoactive substances for 2 weeks before the first testing day and for the duration of the study

Who cannot join

  • Previous significant adverse response to a psychedelic drug
  • Recent or concurrent participation in another study where pharmaceutical compounds will be given
  • Presence of Axis I affective, anxiety, or dissociative disorders
  • Present or antecedent diagnosis of bipolar disorder (I, II, not otherwise specified), schizophrenia, schizoaffective disorder, psychosis, or other disorders from the psychotic spectrum
  • First-degree relatives with present or antecedent schizophrenia, schizoaffective disorder, or bipolar disorder type I
  • History of head trauma, seizures, cancer, or cerebrovascular accidents
Show all 22Show fewer
  • Recent cardiac or brain surgery
  • Current abuse of medication or psychotropic substances according to SCID I criteria
  • Presence of major internal or neurological disorders (including sepsis, pheochromocytoma, thyrotoxicosis, drug-induced fibrosis, familiar or basilar artery migraine)
  • Cardiovascular disease (hypertonia, coronary artery disease, heart insufficiency, myocardial infarction, coronary spastic angina) Version 5, 15/11/2023 16/44
  • Peripheral vascular disease (thromboangiitis obliterans, luetic arteritis, severe arteriosclerosis, thrombophlebitis, Raynaud's disease)
  • Cerebrovascular disease (e.g., stroke, intracranial bleeding / hemorrhage, intracranial aneurysm)
  • Diabetes Type 1/2, Metabolic Syndrome
  • Serious abnormalities in ECG or blood count/chemistry
  • Liver or renal or pulmonary disease
  • Inability to lie still in the scanner for about 90 minutes (e.g., because of sneezing, itching, tremor, pain)
  • Left-handedness
  • Significant radiation exposure (either X-ray or nuclear medicine studies) in the last 12 months
  • Presence of claustrophobia or other contraindications to PET scanning
  • Presence of contraindications to MRI investigations: Magnetic parts in the body (piercings, brain aneurysm clip, implanted neural stimulator/cardiac pacemaker/defibrillator/Swan Ganz catheter/insulin pump, cochlear implant); metal shrapnel or bullet, ocular foreign body (e.g., metal shavings); current or previous job in metalworking industry
  • Current use of medications with significant interaction potential with MAO inhibitors (e.g., antidepressants, antipsychotics, psychostimulants, dopaminergic/serotonergic agents, anticonvulsants)
  • High risk of adverse emotional or behavioral reaction based on investigator's clinical evaluation (e.g., evidence of serious personality disorder, serious current stressors, lack of social support).

Trial locations and contacts

2 sites in 1 country.

Switzerland2 sites

  • Department of Nuclear Medicine, Bern University Hospital

    Bern, 3010

  • Psychiatric University Hospital Zurich

    Zurich, 8032

Other trials in Switzerland

About this study

The few reports on effects of psychedelic substances on cerebral metabolic rate (CMRglc) indicate increases (psilocybin; human FDG-PET) or decreases (LSD, rat autoradiography; 5-MeO-DMT rat autoradiography). There are no reports of effects of DMT and/or harmine on cerebral energy metabolism. The primary objective of this study is thus to assess acute cerebrometabolic effects of harmine/DMT in healthy volunteers using quantitative FDG-PET, that is, to measure CMRglc before and after simultaneous treatment with an oral harmine and DMT formulation developed (and already applied) by the investigators' project partners at the University of Zurich. As a secondary objective, the researchers aim to correlate the time-dependent effects on CMRglc as assessed in the PET images with the time-dependent self-reported intensity of participants' psychedelic experience.

Being tested
N,N-dimethyltryptamine (DMT) + harmine, Placebo
Keywords
Brain, Glucose, PET, FDG, Metabolism, DMT, Harmine, Ayahuasca

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • N,N-dimethyltryptamine (DMT) + harmineDrug

    DMT and harmine are the two most abundant chemicals in the Amazonian hallucinogenic plant brew, Ayahuasca, which is used traditionally in spiritual and healing ceremonies. An oral formulation of these two substances will be tested against placebo in the context of an FDG-PET scan.

  • PlaceboDrug

    Placebo will be administered on one of the study days to compare the effects of DMT and harmine with the effects a placebo administration.

Study groups in NCT06252506
Study groupRoleWhat they receive
Placebo first, intervention secondExperimentalParticipants allocated to this arm receive placebo on their first study day and the active drug under investigation on the second study day.
Receives: Drug: N,N-dimethyltryptamine (DMT) + harmine; Drug: Placebo
Intervention first, placebo secondExperimentalParticipants allocated to this arm receive the active drug under investigation on their first study day and placebo on the second study day.
Receives: Drug: N,N-dimethyltryptamine (DMT) + harmine; Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change from baseline in cerebral metabolic rate for glucose (CMRglc)

    Differences in CMRglc during a placebo PET scan vs. active-drug PET scan are measured.

    Measured: From enrollment to the second PET scan, up to 6 months

Secondary outcomes (12)

  1. Blood Glucose levels

    Glucose levels in blood are measured before and after PET scans to correct PET data to changes in glucose during the scans.

    Measured: From enrollment to the second PET scan, up to 6 months

  2. Plasma concentrations of DMT, harmine, and their metabolites

    Plasma concentrations of DMT, harmine and their main metabolites are assessed at several timepoints, i.e. at baseline, 20, 40, 60, 80, 100, and 180 min after drug or placebo administration. These concentrations serve as a combined outcome measure, as harmine directly influences the metabolism of DMT.

    Measured: From enrollment to the second PET scan, up to 6 months

  3. Aliveness Task

    Behavioral experiment designed to assess the attribution of consciousness and intentionality to animate and inanimate objects.

    Measured: From enrollment to the second PET scan to a maximum of 6 months

  4. Acute Subjective Effects

    Acute substance effects are measured with a questionnaire named APsych and consists of 8 items (i.e. ratings of intensity, challenging, acceptance, clarity, visual hallucinations, emotionality, liking, arousal) rated from 1-10 with 10 being the highest and assessment if bodily or psychiatric symptoms are present are assessed at several timepoints, i.e. at baseline, 20, 40, 60, 80, 100, 120, 140, 160, 180, 240, and 300 min after drug or placebo administration.

    Measured: From enrollment to the second PET scan, up to 6 months

  5. Blood pressure

    Blood pressure is assessed at several timepoints, i.e. at baseline, 20, 40, 80, 180, and 300 min after drug or placebo administration.

    Measured: From enrollment to the second PET scan, up to 6 months

  6. Heart rate

    Heart rate is assessed at several timepoints, i.e. at baseline, 20, 40, 80, 180, and 300 min after drug or placebo administration.

    Measured: From enrollment to the second PET scan, up to 6 months

  7. Challenging Experiences

    Challenging Experiences Questionnaire is administered 240 min after drug or placebo administration. The questionnaire consists of 26 items that are rated from 0 (not at all) to 5 (extreme).

    Measured: From enrollment to the second PET scan, up to 6 months

  8. Mystical Experience

    Mystical Experience Questionnaire is administered 240 min after drug or placebo administration. The questionnaire consists of 30 items that are rated from 0 (not at all) to 5 (extreme).

    Measured: From enrollment to the second PET scan, up to 6 months

  9. Emotional Breakthrough

    Emotional Breakthrough Inventory is administered 240 min after drug or placebo administration. The questionnaire consists of 6 items that are rated from 0 (not at all) to 100 (very much).

    Measured: From enrollment to the second PET scan, up to 6 months

  10. Altered States of Consciousness

    Altered States of Consciousness Questionnaire is administered 240 min after drug or placebo administration. The questionnaire consists of 94 items that are rated from 0 (no, not more than usual) to 100 (yes, much more than usual).

    Measured: From enrollment to the second PET scan, up to 6 months

  11. Attribution of Consciousness Questionnaire

    The Attribution of Consciousness Questionnaire is assessed at baseline (medical screening) and 240 min after drug or placebo administration. The questionnaire consists of 10 items that are rated from 0 (strongly disagree) to 6 (strongly agree).

    Measured: From enrollment to the second PET scan, up to 6 months

  12. Individual Differences in Anthropomorphism

    The Individual Differences in Anthropomorphism Questionnaire is assessed at baseline (medical screening) and 240 min after drug or placebo administration. The questionnaire consists of 30 items that are rated from 0 (not at all) to 10 (very much).

    Measured: From enrollment to the second PET scan, up to 6 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted9 Feb 2024
  2. Study start22 Jan 2024
  3. Primary completion17 Feb 2025
  4. Study completion5 Mar 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
Single blind
Who is masked
Participant
Enrolment
17 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06252506
Sponsor's protocol ID
HaD-PET
Other IDs
320030_204978
Acronym
HaD-PET
Status last verified
Mar 2025
First submitted
1 Feb 2024
Last updated
19 Mar 2025
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Vollenweider FX, Leenders KL, Scharfetter C, Maguire P, Stadelmann O, Angst J. Positron emission tomography and fluorodeoxyglucose studies of metabolic hyperfrontality and psychopathology in the psilocybin model of psychosis. Neuropsychopharmacology. 1997 May;16(5):357-72. doi: 10.1016/S0893-133X(96)00246-1.

    PubMed 9109107

  • Berlowitz I, Egger K, Cumming P. Monoamine Oxidase Inhibition by Plant-Derived beta-Carbolines; Implications for the Psychopharmacology of Tobacco and Ayahuasca. Front Pharmacol. 2022 May 2;13:886408. doi: 10.3389/fphar.2022.886408. eCollection 2022.

    PubMed 35600851

  • Egger K, Gudmundsen F, Jessen NS, Baun C, Poetzsch SN, Shalgunov V, Herth MM, Quednow BB, Martin-Soelch C, Dornbierer D, Scheidegger M, Cumming P, Palner M. A pilot study of cerebral metabolism and serotonin 5-HT2A receptor occupancy in rats treated with the psychedelic tryptamine DMT in conjunction with the MAO inhibitor harmine. Front Pharmacol. 2023 Sep 28;14:1140656. doi: 10.3389/fphar.2023.1140656. eCollection 2023.

    PubMed 37841918

  • Egger K, Bozsak R, Aicher HD, Sari H, Poetzsch SN, Rominger A, Martin-Soelch C, Smallridge JW, Dornbierer D, Quednow BB, Scheidegger M, Cumming P. Global increases in brain glucose metabolism following acute N,N-dimethyltryptamine and harmine administration in healthy volunteers: A randomised [18F]FDG-PET study. J Cereb Blood Flow Metab. 2026 Jun 1:271678X261454172. doi: 10.1177/0271678X261454172. Online ahead of print.

    PubMed 42220002

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing N,N-dimethyltryptamine (DMT) + harmine in people with Neuropharmacological Investigation of Ayahuasca Constituents DMT and Harmine, run by Insel Gruppe AG, University Hospital Bern at 2 sites 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 7 inclusion and 22 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 19 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites 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. 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?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

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?

Change from baseline in cerebral metabolic rate for glucose (CMRglc) (time frame: From enrollment to the second PET scan, up to 6 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06252506, which also lists 4 linked publications.

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 19 Mar 2025.

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