LSD Occupancy of the Serotonin 2A Receptor in the Human Brain (dOccLS)

This early-phase, interventional trial (n=40) investigates LSD occupancy at the serotonin 2A receptor (5-HT2AR) in the human brain. Healthy participants aged 18-75 will receive a single dose of LSD ranging from 25 to 200 micrograms equivalent freebase.

The study, initiated on November 8, 2023, is expected to be completed by December 2024. The primary objective is to quantify the relationship between LSD dose, plasma LSD levels, and 5-HT2AR occupancy using positron emission tomography (PET) scans. The trial will also assess subjective drug intensity and functional brain activity via functional MRI (fMRI) and other measures. Dr Gitte M Knudsen leads the study at the Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.

Topic Healthy Subjects Neuroscience
Compound LSD
Country Denmark
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Trial Details



Trial Number

Sponsors & Collaborators

Copenhagen University Hospital Rigshospitalet
The university hospital in Copenhagen, the Rigshospitalet, is Denmark's most prestigious (and largest) hospital. Literally translated, the name stands for 'Hospital of the Realm.' Researchers here are working on at least three psychedelic trials with psilocybin.

Papers

Molecular, haemodynamic, and functional effects of LSD in the human brain
This pre-print simultaneous PET-MRI study (first of its kind) demonstrates that LSD increases global cerebral blood flow and internal carotid artery flow without affecting artery diameter (opposite to psilocybin's effects), while decreasing global connectivity (particularly in visual networks) and increasing network entropy and spatial complexity, with researchers also observing an anticlockwise hysteresis loop (dynamic lag between an input and an output) between plasma levels and subjective effects that challenges existing hypotheses about psychedelic mechanisms of action.

Data attribution

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