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Sys Stybe Johansen

13 papers in the library · 775 citations · publishing 2005-2026

Papers

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Case Report: Repeated low doses of psilocybin reduce perceived symptom severity but fail to restore cognitive flexibility in a case of severe obsessive-compulsive disorder: an observational case study of identical twins.

Frontiers in Psychiatry 2026 Sivert Drange, Jacob Cohen, Sys Stybe Johansen et al. 1 citation

Obsessive-Compulsive Disorder (OCD) can present significant challenges to individuals mental health, characterized by intrusive thoughts and repetitive maladaptive behaviors. Recent research into alternative treatments has highlighted psychedelics, notably psilocybin, for their potential therapeutic benefits in various psychiatric disorders, including OCD. This case study evaluated the impact...

Molecular, haemodynamic and functional effects of LSD in the human brain

medRxiv June 18, 2025 Drummond E-Wen Mcculloch, Kristian Larsen, Annette Johansen et al. preprint

In this study, we provide the first study to integrate molecular and functional neuroimaging during psychedelic drug effects in humans. Using simultaneous PET-MRI technology, we describe multiple brain actions of lysergic acid diethylamide (LSD) in healthy volunteers. We quantify the occupancy of LSD at cerebral serotonin 2A receptors and show that LSD increases global cerebral blood flow and...

Single-dose psilocybin therapy for alcohol use disorder: Pharmacokinetics, feasibility, safety and efficacy in an open-label study

Journal of Psychopharmacology February 28, 2025 Dea Siggaard Stenbæk, Emil Deleuran Poulsen, Marie Katrine Klose Nielsen et al. 15 citations

Background: Psilocybin, a serotonin 2A receptor agonist with psychedelic properties, shows promise as a novel treatment for alcohol use disorder (AUD). While current studies involve two dosing sessions, the effects of a single dose have not been investigated. Aims: To investigate the pharmacokinetics, feasibility, safety and efficacy of single-dose psilocybin therapy in AUD. Methods: This...

Repeated low doses of psilocybin reduces perceived symptom severity of obsessive-compulsive disorder, but fails to restore cognitive flexibility: A case study of identical twins

December 30, 2024 Sivert Drange, Jacob Cohen, Sys Stybe Johansen et al. 1 citation preprint

Background: Obsessive-Compulsive Disorder (OCD) presents significant challenges to individuals mental health, characterized by intrusive thoughts and repetitive maladaptive behaviours. Recent exploration into alternative treatments has spotlighted psychedelics, notably psilocybin, for their potential therapeutic benefits in different psychiatric disorders, including OCD. This case study delves...

Single-Dose Psilocybin Therapy for Alcohol Use Disorder: Pharmacokinetics, Feasibility, Safety, and Efficacy in an Open-Label Study

Research Square August 23, 2024 Mathias E. Jensen, Dea Siggaard Stenbæk, Catharina Messell et al. 1 citation

Abstract Background Psilocybin, a serotonin 2A receptor agonist with psychedelic properties, shows promise as a novel treatment for alcohol use disorder (AUD). While current studies involve two dosing sessions, the effects a single dose have not been investigated. Aims To investigate the pharmacokinetics, feasibility, safety, and efficacy of single-dose psilocybin therapy in AUD. Methods This...

CCH attack frequency reduction after psilocybin correlates with hypothalamic functional connectivity

Headache The Journal of Head and Face Pain 2024 Anja Sofie Petersen, Inger Marie Sørensen, Harald Schiønning et al. 29 citations

Abstract Objective To evaluate the feasibility and prophylactic effect of psilocybin as well as its effects on hypothalamic functional connectivity (FC) in patients with chronic cluster headache (CCH). Background CCH is an excruciating and difficult‐to‐treat disorder with incompletely understood pathophysiology, although hypothalamic dysfunction has been implicated. Psilocybin may have...

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...

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...

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.

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...

In Vivo Imaging of Cerebral Serotonin Transporter and Serotonin2A Receptor Binding in 3,4-Methylenedioxymethamphetamine (MDMA or “Ecstasy”) and Hallucinogen Users

Archives of General Psychiatry June 6, 2011 David Erritzøe, Vibe G. Frøkjær, Klaus K. Holst et al. 86 citations

We found evidence that MDMA but not hallucinogen use is associated with changes in the cerebral presynaptic serotonergic transmitter system. Because hallucinogenic drugs primarily have serotonin(2A) receptor agonistic actions, we conclude that the negative association between MDMA use and cerebral SERT binding is mediated through a direct presynaptic MDMA effect rather than by the serotonin(2A)...

Determination of amphetamine, methamphetamine, MDA and MDMA in human hair by GC‐EI‐MS after derivatization with perfluorooctanoyl chloride

Scandinavian Journal of Clinical and Laboratory Investigation October 21, 2008 Sys Stybe Johansen, Jakob Jornil 25 citations

The aim of this study was to develop a quantitative gas chromatography mass spectrometry (GC-MS) method to determine the classical amphetamines and their methylenedioxylated derivatives in human hair. The procedure involved liquid-liquid extraction of hydrolysed hair spiked with deuterated internal standards and direct derivatization with perfluorooctanoyl chloride. After evaporation of the...

Liquid chromatography–tandem mass spectrometry determination of LSD, ISO-LSD, and the main metabolite 2-oxo-3-hydroxy-LSD in forensic samples and application in a forensic case

Journal of Chromatography B January 29, 2005 Sys Stybe Johansen, Jytte Lundsby Jensen 41 citations

A liquid chromatography mass spectrometric (LC/MS/MS) method has been developed for the determination of LSD, iso-LSD and the metabolite 2-oxo-3-hydroxy-LSD in forensic applications. The procedure involves liquid-liquid extraction of the analytes and LSD-D3 (internal standard) from 1.0 g whole blood or 1.0 ml urine with butyl acetate at pH 9.8. Confirmation and quantification were done by...