Clinical Trial
A research study that tests a medical intervention on human participants under structured protocols.
A clinical trial is a research study designed to test a medical intervention on human participants under carefully controlled conditions. Trials proceed through phases that increase in size and rigor as evidence accumulates.
Phase I trials are small and focused on safety, tolerability, and basic pharmacokinetics. Phase II trials evaluate efficacy in a target patient population, usually with a few dozen to a few hundred participants. Phase III trials are large, multi-site, randomized controlled studies designed to provide the evidence base for regulatory approval.
Key features that distinguish a rigorous trial from a weaker one include randomization (assigning participants to groups by chance), blinding (preventing participants and assessors from knowing which group they are in), an active comparator (rather than a passive placebo), and pre-registration of primary outcomes before data collection begins.
Psilocybin research has progressed through Phase II for several conditions, with Phase III trials underway for treatment-resistant depression.