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Completed

NCT Number: NCT06252506

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

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.

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Key information

Conditions

Neuropharmacological Investigation of Ayahuasca Constituents DMT and Harmine

Age range

25 year–45 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 1

Primary location

Department of Nuclear Medicine, Bern University Hospital, Bern, Switzerland

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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
  • 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).

Treatment and study plan

N,N-dimethyltryptamine (DMT) + harmine

Drug

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.

Placebo

Drug

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

Primary outcomes

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

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

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

Secondary outcomes

  1. Blood Glucose levels

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

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

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

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

    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.

  3. Aliveness Task

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

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

  4. Acute Subjective Effects

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

    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.

  5. Blood pressure

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

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

  6. Heart rate

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

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

  7. Challenging Experiences

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

    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).

  8. Mystical Experience

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

    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).

  9. Emotional Breakthrough

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

    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).

  10. Altered States of Consciousness

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

    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).

  11. Attribution of Consciousness Questionnaire

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

    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).

  12. Individual Differences in Anthropomorphism

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

    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).

Sponsors and collaborators

Lead sponsor

Insel Gruppe AG, University Hospital Bern

Other

Collaborators

  • Psychiatric University Hospital, Zurich

Registry information

Acronym: HaD-PET

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Feb 9, 2024
Registry last updated
Mar 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.