Role of the Serotonin 2A Receptor in Psilocybin-induced Altered States of Consciousness

This interventional, crossover trial (n=16) will investigate the role of the serotonin 2A receptor in psilocybin-induced altered states of consciousness, with participants receiving varying doses of psilocybin (5mg, 10mg, 20mg, 40mg) and a 40mg ketanserin pretreatment.

Conducted by University Hospital Basel in Switzerland, the study aims to characterise the subjective effects of psilocybin at different doses using modern psychometric tools, and to examine how plasma concentrations of psilocybin correlate with its effects. The study will also explore the contribution of the serotonin 2A receptor to psilocybin’s influence on consciousness. Participants will undergo randomised and counterbalanced treatments, with at least 10 days between each dose administration.

Researchers will assess the subjective experiences of participants, including mood, perception, and cognition, and correlate these with physiological measures such as heart rate, blood pressure, and sleep patterns. Additionally, the study will measure plasma concentrations of psilocybin and its metabolites to understand the pharmacokinetics of the drug.

Topic Healthy Subjects
Compound Psilocybin
Country Switzerland
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Trial Details



Trial Number

Sponsors & Collaborators

University of Basel
The University of Basel Department of Biomedicine hosts the Liechti Lab research group, headed by Matthias Liechti.

Data attribution

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