The Neurobiological Effect of 5-HT2AR Modulation

Phase 1 Recruiting 200 enrolled Gitte Moos Knudsen

Non-randomizedSequentialSingle-blindBasic science

Summary

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.

Timeline

Start: 2017-03-03
Primary completion: 2030-06-01
Completion: 2030-06-01

Publications

Johansen A, Plaven-Sigray P, Madsen MK, Sondergaard A, Messel C, Geisler M, Nasser A, McCulloch DE, Beliveau V, Vassilieva A, Lund A, Lehel S, Ozenne B, Stenbaek DS, Fisher PM, Svarer C, Knudsen GM. Psilocybin's effect on human brain synaptic plasticity. Transl Psychiatry. 2026 Jul 15. doi: 10.1038/s41398-026-04285-y. Online ahead of print.
Brendstrup-Brix K, Ozenne B, Fisher PM, Stenbaek DS, Petersen AS, Armand S, McCulloch DE, Marstrand-Joergensen MR, Ulv Larsen SM, Johansen A, Jensen RH, Knudsen GM, Madsen MK. Effects of psilocybin on sleep quality and brain microstructure in chronic cluster headache. J Psychopharmacol. 2026 May 29:2698811261449380. doi: 10.1177/02698811261449380. Online ahead of print.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Ketanserin	Small molecule	—	Oral
Subject	Psilocybin	Other / unclassified	0.3 mg/kg	Oral
Subject	Psilocybin	Other / unclassified	25 mg	Oral

Indications

No indication recorded.