This randomised, quadruple-masked, crossover trial (n=24) will assess the pharmacokinetics, safety and subjective effects of DDH-LSD, a novel LSD-like lysergamide, compared with oral LSD and placebo in healthy adult volunteers aged 18–65, with primary aims to determine an effective DDH-LSD dose and to compare duration of action and elimination half-life. The study has two parts: Substudy 1 is an open-label dose‑escalation in healthy participants to identify a DDH-LSD dose that produces clear but tolerable psychoactive effects. Substudy 2 is a randomised, double‑blind, placebo‑controlled crossover in which each participant receives single oral administrations of the selected DDH-LSD dose, 0.1 mg LSD, and placebo on separate supervised study days; each session lasts approximately 13 hours with monitoring of pharmacokinetics, subjective effects, autonomic/physiological responses and safety parameters to provide first‑in‑human characterisation of DDH-LSD.
This study investigates DDH-LSD, a novel LSD-like compound expected to have a shorter duration of action than LSD. In healthy volunteers, pharmacokinetics, safety, and subjective effects, will be assessed and compare with LSD in a controlled cross-over study.
Participants receive a single dose of DDH-LSD at the dose determined in Substudy 1. The session lasts approximately 13 hours with monitoring of subjective, physiological, and pharmacokinetic effects.
Participants receive a single 0.1 mg dose of LSD. The session lasts approximately 13 hours with monitoring of subjective, physiological, and pharmacokinetic effects.
Participants receive a placebo dose. The session lasts approximately 13 hours with monitoring of the same parameters to control for expectancy and procedural effects.