Early‑Phase interventional dose-ranging study (n=40) assessing LSD single doses (25–200 µg) to quantify 5‑HT2A receptor occupancy in healthy participants using [11C]CIMBI‑36 PET/MR.
Healthy participants (18–75 years) receive a single oral dose of LSD (one of 25–200 µg) in a single‑blinded, dose‑ranging design to characterise dose–plasma–receptor occupancy relationships.
Participants undergo baseline and two post‑dose [11C]CIMBI‑36 PET scans in a simultaneous PET/MR scanner at peak and declining effects; repeated venous sampling quantifies plasma LSD and repeated subjective intensity ratings (0–10) capture acute effects.
Single-blind dose-ranging group; each participant receives one single oral dose (25–200 µg) with simultaneous PET/MR during acute effects.
Oral D‑tartrate drinking solution (water/ethanol 20% m/m); participants single-blinded to dose (one of 25,50,75,100,125,150,175,200 µg).