A Phase 1 interventional study of Psilocybine and Ketanserin in Basic Science, sponsored by Gitte Moos Knudsen. Recruiting at 1 site in Denmark. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2024-12-16.
Sponsored by Gitte Moos Knudsen · Phase 1, Interventional, and Basic science
The investigators wish to investigate neurobiological effects of serotonin 2A receptor modulation in healthy volunteers, contrasting effects of an agonist (psilocybin) and an antagonist (ketanserin). Magnetic resonance imaging (MRI) and positron emission tomography (PET) will be used as neuroimaging tools.
This project applies an experimental medicine strategy coupled with human functional and molecular neuroimaging to elucidate the effects of 5-HT2A receptor (5-HT2AR) modulation on brain function and mood in healthy individuals. We compare psilocybin (5-HT2AR agonist) and ketanserin (5-HT2AR antagonist) effects on brain function to identify neural mechanisms mediating the clinical effects of psilocybin and, more broadly, to establish this comparative strategy as a pathway for delineating pharmacological effects on the brain in humans.
Gitte Moos Knudsen is the lead sponsor of 8 studies on the registry; 2 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria (For Subprojects 1, 2a, 2b, and 3):
Exclusion Criteria (For Subproject 2c):
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
After baseline MRI \& 5-HT2AR PET-imaging, participants will be allocated to undergo either one oral dose of psilocybine or one oral dose of ketanserin. After drug administration, participants will undergo two CIMBI-36 PET scans.
Drug: Psilocybine · Drug: Ketanserin
After baseline MRI \& CIMBI-36 PET-imaging, participants will receive one dose of oral psilocybine intervention. One and 12 weeks after dosing, participants will undergo post-intervention PET-scan. Subproject B: After baseline MRI \& UCB-J PET-imaging, participants will receive one dose of oral psilocybine intervention. One week after dosing, participants will undergo post-intervention UCB-J PET-scan. Subproject C: After baseline MR imaging, participants will receive one dose of oral psilocybine (25 mg) or placebo. One month after dosing, participants will undergo a post-intervention MRI scan.
Drug: Psilocybine
After baseline MRI scanning and CIMBI-36 PET, participants will undergo one psilocybine-intervention fMRI scan and one ketanserin-intervention fMRI scan. If P2 shows there are long term effects of psilocybine on 5-HT2AR levels, psilocybine will be fixed as the second intervention. If not, interventions will be randomized.
Drug: Psilocybine · Drug: Ketanserin
Oral dose of psilocybine.
Also known as: Psilocybin
Oral dose of ketanserin.
Also known as: Ketensin
Psilocin/ketanserin blood concentrations and 5-HT2A receptor occupancy (i.e., binding potential).
The investigators aim to model relations psilocin/ketanserin blood drug concentrations and receptor occupancy, using C11-Cimbi-36 PET imaging.
Time frame: Change in Cimbi-36 binding potential from baseline PET to intervention PET 1 and PET 2 scans (same day for psilocybin, and two consecutive days for ketanserin).
Effects of psilocybin on Cimbi-36 binding potential at baseline and at one and twelve weeks
Cimbi-36 PET scan binding potential at baseline and at one-week post psilocybin, and potentially also at 12 weeks post psilocybin.
Time frame: Change in Cimbi-36 binding potential from baseline to one week post psilocybin (and potentially also at 12 weeks after psilocybin).
Effects of psilocybin and ketanserin on brain function assessed with fMRI and PET
Correlations between blood levels of ketanserin and psilocin and the estimated associated receptor occupancy with functional MRI neuroimaging data, including resting state networks. Changes in synaptic density will be assessed with 11C-UCB-J PET scans before and 1 week after psilocybin intervention.
Time frame: Changes in functional connectivity (fMRI) from Baseline MR to intervention MR scans for ketanserin (one or three weeks after baseline MR) and psilocybin (one or three weeks after baseline)
Effects of psilocybin on UCB-J binding potential at baseline and at one week
Project 2, Subproject B. UCB-J PET scan binding potential at baseline and at one-week post psilocybin.
Time frame: Change in UCB-J binding potential from baseline to one week post psilocybin.
Effects of psilocybin on brain function assessed with fMRI at baseline and one month
Project 2, Subproject C. Resting-state and task-based fMRI measures at baseline and one month post psilocybin.
Time frame: Change in fMRI measures from baseline to one month post psilocybin
Anxiety Outcome Measure 1: Acute psychological effects as assessed using Challenging Experiences Questionnaire (CEQ).
Differences in CEQ scores between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Likert-scale ranging from 0 (Not all all) to 5 (Extremely; More than ever). Higher scores thus reflect a more challenging experience. Project 2, Subproject C. PsiloZonic.
Time frame: Immediately post-intervention.
Anxiety Outcome Measure 2: Acute psychological effects as assessed using 5D-Altered States of Consciousness (5D-ASC) scale.
Differences in 5D-ASC anxiety scores between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Visual analogue scale (VAS) scale ranging from 0 (No, not more than usually) to 100 (Yes, much more than usually). Higher scores on dimension anxiety thus reflect more anxiety. Project 2, Subproject C. PsiloZonic.
Time frame: Immediately post-intervention.
Anxiety Outcome Measure 3: Acute psychological effects as assessed using Extended Subjective Drug Intensity (eSDI) scale.
Differences in eSDI anxiety scores between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Likert-scale ranging from 0 (Not all all) to 10 (Very much). Higher scores on item anxiety thus reflect more anxiety. Project 2, Subproject C. PsiloZonic.
Time frame: During intervention.
Transformative Experiences Outcome Measure 1: Acute psychological effects as assessed using Mystical Type Experiences Questionnaire (MEQ) scale.
Differences in MEQ scores between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Likert-scale ranging from 0 (Not all all) to 5 (Extremely). Higher scores thus reflect a more profound mystical type experience. Project 2, Subproject C. PsiloZonic.
Time frame: Immediately post-intervention.
Transformative Experiences Outcome Measure 2: Acute psychological effects as assessed using Psychological Insights Questionnaire (PIQ) scale.
Differences in PIQ scores between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Likert-scale ranging from 0 (Not all all) to 5 (Extremely). Higher scores thus reflect more psychological insight. Project 2, Subproject C. PsiloZonic.
Time frame: Immediately post-intervention.
Transformative Experiences Outcome Measure 3: Acute psychological effects as assessed using Emotional Breakthrough Questionnaire (EBI) scale.
Differences in EBI scores between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Visual analogue scale (VAS) scale ranging from 0 (No, not more than usually) to 100 (Yes, much more than usually). Higher scores thus reflect more emotional breakthrough. Project 2, Subproject C. PsiloZonic.
Time frame: Immediately post-intervention.
Persisting Effects Outcome Measure 1: Persisting psychological effects as assessed using Persisting Effects Questionnaire (PEQ) scale.
Differences in PEQ scores will be assessed between groups (psilocybin with music compared to psilocybin without music). Effects are measured on a Likert-scale ranging from 0 (Not all all) to 5 (Extremely). Higher scores thus reflect more persisting effects. Project 2, Subproject C. PsiloZonic.
Time frame: One and three months post-intervention.
Plan to share: Yes — Via database of Center for Integrated Molecular Brain Imaging (Knudsen et al 2016, NeuroImage) data will be available for neuroscience research community contingent on approval by scientific board.
Supporting information: Study protocol
Time frame: Upon project completion
Access criteria: All researchers can request access to data from the database by completing a standardized application form to provide detailed information about the specific database request. The application form and guidelines are available here. Please note that there are some formal requirements that must be fulfilled if the data request is from an international researcher. For example we do not have permission for sharing data outside of the EU, so researchers from a non-EU country will have to come here to work on the data instead.
Data sharing details ↗ · cimbi.dk
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Started Mar 2017 (actual). Primary completion is estimated for Jun 2030, 158 months after the start.
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Studies of the drug tested here: Ketanserin
Gitte Moos Knudsen