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Gitte M. Knudsen

Rigshospitalet, Copenhagen University Hospital

54 papers in the library · 2,827 citations · publishing 2010-2026

Papers

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Psilocybin-induced reduction in chronic cluster headache attack frequency correlates with changes in hypothalamic functional connectivity

medRxiv July 10, 2022 M. Madsen, Anja Sofie Petersen, Dea Siggaard Stenbæk et al. 5 citations preprint

Abstract Chronic cluster headache (CCH) is an excruciating disorder of unknown pathophysiology, but hypothalamic dysfunction has been implicated. CCH is difficult to treat but on a case-basis, the psychedelic compound psilocybin is said to have beneficial effects. In this first-ever clinical trial ( NCT04280055 ), we evaluate in a small open-label study of CCH patients the feasibility and...

Sustained effects of single doses of classical psychedelics in humans.

Neuropsychopharmacology June 21, 2022 Gitte M. Knudsen 56 citations

The serotonergic classical psychedelics include compounds that primarily activate the brain's serotonin 2 A receptor (5-HT2AR), such as LSD, psilocybin, and DMT (ayahuasca). The acute effects of these compounds are well-known as are their ability to increase the emotional state both in healthy people and in those with neuropsychiatric disorders. In particular psilocybin, the psychoactive...

Psilocybin-Induced Mystical-Type Experiences are Related to Persisting Positive Effects: A Quantitative and Qualitative Report

Frontiers in Pharmacology March 9, 2022 Drummond E-Wen Mcculloch, Maria Zofia Grzywacz, Martin Bruun Madsen et al. 91 citations

Psychedelic drugs such as psilocybin have shown substantial promise for the treatment of several psychiatric conditions including mood and addictive disorders. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study (NCT03289949), 35 medium-high doses of psilocybin were administered to 28...

Psilocybin modulation of dynamic functional connectivity is associated with plasma psilocin and subjective effects

medRxiv December 17, 2021 Anders S. Olsen, Anders Lykkebo-Valløe, Brice Ozenne et al. 4 citations preprint

Abstract Background Psilocin, the neuroactive metabolite of psilocybin, is a serotonergic psychedelic that induces an acute altered state of consciousness, evokes lasting changes in mood and personality in healthy individuals, and has potential as an antidepressant treatment. Examining the acute effects of psilocin on resting-state dynamic functional connectivity implicates network-level...

A Quantitative and Qualitative Report of Psilocybin Induced Mystical-Type Experiences and Their Relation to Lasting Positive Effects

December 14, 2021 Drummond E-Wen Mcculloch, Maria Zofia Grzywacz, M. Madsen et al. 2 citations preprint

Psychedelic drugs such as psilocybin are under investigation for the treatment of several psychiatric conditions. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study, 35 medium-high doses of psilocybin were administered to 28 healthy volunteers (12 females). By the end of the dosing day,...

Psilocybin-induced changes in brain network integrity and segregation correlate with plasma psilocin level and psychedelic experience.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology September 1, 2021 Martin K Madsen, Dea S Stenbæk, Albin Arvidsson et al. 132 citations

The emerging novel therapeutic psilocybin produces psychedelic effects via engagement of cerebral serotonergic targets by psilocin (active metabolite). The serotonin 2A receptor critically mediates these effects by altering distributed neural processes that manifest as increased entropy, reduced functional connectivity (FC) within discrete brain networks (i.e., reduced integrity) and increased...

Lasting effects of a single psilocybin dose on resting-state functional connectivity in healthy individuals

Journal of Psychopharmacology June 30, 2021 Drummond E-Wen Mcculloch, Martin Bruun Madsen, Dea Siggaard Stenbæk et al. 79 citations

Background: Psilocybin is a psychedelic drug that has shown lasting positive effects on clinical symptoms and self-reported well-being following a single dose. There has been little research into the long-term effects of psilocybin on brain connectivity in humans. Aim: Evaluate changes in resting-state functional connectivity (RSFC) at 1 week and 3 months after one psilocybin dose in 10 healthy...

Default mode network functional connectivity negatively associated with trait openness to experience

Social Cognitive and Affective Neuroscience April 23, 2021 Maja Rou Marstrand-Joergensen, M. Madsen, Dea Siggaard Stenbæk et al. 20 citations

Evaluating associations between the five-factor personality domains and resting-state functional connectivity networks (e.g. default mode network, DMN) highlights distributed neurobiological systems linked to behaviorally relevant phenotypes. Establishing these associations can highlight a potential underlying role for these neural pathways in related clinical illness and treatment response....

A Single Dose of Psilocybin Increases Synaptic Density and Decreases 5-HT2A Receptor Density in the Pig Brain

International Journal of Molecular Sciences January 15, 2021 Nakul Ravi Raval, Annette Johansen, Lene Lundgaard Donovan et al. 191 citations

A single dose of psilocybin, a psychedelic and serotonin 2A receptor (5-HT2AR) agonist, may be associated with antidepressant effects. The mechanism behind its antidepressive action is unknown but could be linked to increased synaptogenesis and down-regulation of cerebral 5-HT2AR. Here, we investigate if a single psychedelic dose of psilocybin changes synaptic vesicle protein 2A (SV2A) and...

Effects of a single dose of psilocybin on behaviour, brain 5-HT2A receptor occupancy and gene expression in the pig

European Neuropsychopharmacology December 4, 2020 Lene Lundgaard Donovan, Jens Vilstrup Johansen, Nídia Fernandez Ros et al. 45 citations

Psilocybin has in some studies shown promise as treatment of major depressive disorder and psilocybin therapy was in 2019 twice designated as breakthrough therapy by the U.S. Food and Drug Administration (FDA). A very particular feature is that ingestion of just a single dose of psilocybin is associated with lasting changes in personality and mood. The underlying molecular mechanism behind its...

Brain serotonin 2A receptor binding predicts subjective temporal and mystical effects of psilocybin in healthy humans

Journal of Psychopharmacology October 8, 2020 Dea Siggaard Stenbæk, M. Madsen, Brice Ozenne et al. 81 citations

Background: Psilocybin is a serotonergic psychedelic with psychoactive effects mediated by serotonin 2A receptor (5-HT2AR) activation. It produces an acute psychedelic altered state of consciousness with a unique phenomenology that can be temporally characterized by three intensity phases: onset of psychoactive effect, a peak plateau and return to normal consciousness. Aims: We evaluated...

Dynamic coupling of whole-brain neuronal and neurotransmitter systems

Proceedings of the National Academy of Sciences April 13, 2020 Morten L. Kringelbach, Josephine Cruzat, Joana Cabral et al. 326 citations

Significance In a technical tour de force, we have created a framework demonstrating the underlying fundamental principles of bidirectional coupling of neuronal and neurotransmitter dynamical systems. Specifically, in the present study, we combined multimodal neuroimaging data to causally explain the functional effects of specific serotoninergic receptor (5-HT 2A R) stimulation with psilocybin...

A single psilocybin dose is associated with long-term increased mindfulness, preceded by a proportional change in neocortical 5-HT2A receptor binding

European Neuropsychopharmacology March 4, 2020 M. Madsen, Patrick M. Fisher, Dea Siggaard Stenbæk et al. 189 citations

A single dose of the serotonin 2A receptor (5-HT2AR) agonist psilocybin can have long-lasting beneficial effects on mood, personality, and potentially on mindfulness, but underlying mechanisms are unknown. Here, we for the first time conduct a study that assesses psilocybin effects on cerebral 5-HT2AR binding with [11C]Cimbi-36 positron emission tomography (PET) imaging and on personality and...

Sleep deprivation rapidly upregulates serotonin 2A receptor expression via the immediate early gene Egr3

bioRxiv Preprint Server February 23, 2020 X. Zhao, K. T. Meyers, A. Mcbride et al. 1 citation preprint

Serotonin 2A receptors (5-HT2ARs) mediate the effects of hallucinogenic drugs and antipsychotic medications, and are reduced in schizophrenia patients’ brains. However, the mechanisms that regulate 5-HT2AR expression remain poorly understood. We show that an environmental stimulus, sleep deprivation, upregulates 5-HT2ARs in the mouse frontal cortex (FC) in just 6-8 hours. This induction...

Microdosing psychedelics: More questions than answers? An overview and suggestions for future research

Journal of Psychopharmacology July 14, 2019 Livia Ng, Luca Pani, Anaïs Soula et al.

Background: In the past few years, the issue of ‘microdosing’ psychedelics has been openly discussed in the public arena where claims have been made about their positive effect on mood state and cognitive processes such as concentration. However, there are very few scientific studies that have specifically addressed this issue, and there is no agreed scientific consensus on what microdosing is....

Correction: Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels

Neuropsychopharmacology March 8, 2019 M. Madsen, Patrick M. Fisher, Daniel Burmester et al. 21 citations correction

The original version of this article contained an error in the labelling of Figures 2 and 3. While the captions and figures themselves are correct, in order to correspond with the in-text references, they have now been re-numbered in both the PDF and HTML versions of the article.

Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers.

J Psychopharmacol February 28, 2019 David Erritzøe, James Smith, Patrick M. Fisher et al. 95 citations

Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers.

Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels

Neuropsychopharmacology January 26, 2019 M. Madsen, Patrick M. Fisher, Daniel Burmester et al. 505 citations

The main psychedelic component of magic mushrooms is psilocybin, which shows promise as a treatment for depression and other mental disorders. Psychedelic effects are believed to emerge through stimulation of serotonin 2A receptors (5-HT2ARs) by psilocybin's active metabolite, psilocin. We here report for the first time the relationship between intensity of psychedelic effects, cerebral 5-HT2AR...

Trait Openness and serotonin 2A receptors in healthy volunteers: A positron emission tomography study

Human Brain Mapping January 11, 2019 Dea Siggaard Stenbæk, Sara Kristiansen, Daniel Burmester et al. 11 citations

Abstract Recent research found lasting increases in personality trait Openness in healthy individuals and patients after administration of the serotonin 2A receptor (5‐HT 2A R) agonist psilocybin. However, no studies have investigated whether 5‐HT 2A R availability as imaged using positron emission tomography (PET) is associated with this trait. In 159 healthy individuals (53 females), the...

Whole-Brain Multimodal Neuroimaging Model Using Serotonin Receptor Maps Explains Non-linear Functional Effects of LSD.

Curr Biol September 27, 2018 Gustavo Deco, Josephine Cruzat, Joana Cabral et al. 246 citations

Understanding the underlying mechanisms of the human brain in health and disease will require models with necessary and sufficient details to explain how function emerges from the underlying anatomy and is shaped by neuromodulation. Here, we provide such a detailed causal explanation using a whole-brain model integrating multimodal imaging in healthy human participants undergoing manipulation...

Serotonergic neurotransmission in emotional processing: New evidence from long-term recreational poly-drug ecstasy use

Journal of Psychopharmacology September 6, 2016 Helle Ruff Laursen, Susanne Henningsson, Julian Macoveanu et al. 8 citations

The brain’s serotonergic system plays a crucial role in the processing of emotional stimuli, and several studies have shown that a reduced serotonergic neurotransmission is associated with an increase in amygdala activity during emotional face processing. Prolonged recreational use of ecstasy (3,4-methylene-dioxymethamphetamine [MDMA]) induces alterations in serotonergic neurotransmission that...

Metabolic Fate of Hallucinogenic NBOMes

Chemical Research in Toxicology December 16, 2015 Sebastian Leth-Petersen, Charlotte Gabel‐Jensen, Nic Gillings et al. 43 citations

2,5-Dimethoxy-N-benzylphenethylamines (NBOMes) are very potent 5-HT2AR agonists. Illicit use of these psychedelic compounds has emerged in recent years, and several fatalities have been linked to their recreational use. In its [(11)C]-labeled form, one NBOMe (25B-NBOMe) was recently developed as a PET-ligand for clinical investigations of 5HT2AR ([(11)C]Cimbi-36). Herein, we have identified the...

Open and Calm – A randomized controlled trial evaluating a public stress reduction program in Denmark

BMC Public Health December 1, 2015 Christian Jensen, Jon Lansner, Anders Petersen et al. 53 citations

BACKGROUND: Prolonged psychological stress is a risk factor for illness and constitutes an increasing public health challenge creating a need to develop public interventions specifically targeting stress and promoting mental health. The present randomized controlled trial evaluated health effects of a novel program: Relaxation-Response-based Mental Health Promotion (RR-MHP). METHODS: The...

Serotonin 2A Receptor Agonist Binding in the Human Brain with [11C]Cimbi-36

Journal of Cerebral Blood Flow & Metabolism April 30, 2014 Anders Ettrup, Sofi Da Cunha‐bang, Brenda Mcmahon et al. 106 citations

[ 11 C]Cimbi-36 was recently developed as a selective serotonin 2A (5-HT 2A ) receptor agonist radioligand for positron emission tomography (PET) brain imaging. Such an agonist PET radioligand may provide a novel, and more functional, measure of the serotonergic system and agonist binding is more likely than antagonist binding to reflect 5-HT levels in vivo. Here, we show data from a...

In abstinent MDMA users the cortisol awakening response is off-set but associated with prefrontal serotonin transporter binding as in non-users

The International Journal of Neuropsychopharmacology February 14, 2014 Vibe G. Frøkjær, David Erritzøe, Klaus K. Holst et al. 19 citations

Serotonergic signaling is considered critical for an appropriate adaptation to stress. We have previously observed that in healthy volunteers, prefrontal serotonin transporter (SERT) binding is positively associated with hypothalamic-pituitary-adrenal (HPA)-axis output in terms of the cortisol awakening response (CAR). Here, we tested (1) if such a correlation persists in a human model of...