Compass Pathways achieved its primary endpoint in the largest phase 3 study of psilocybin for treatment-resistant depression, demonstrating a statistically significant reduction in depressive symptoms versus placebo. Despite this clinical milestone, investor enthusiasm was muted, reflected in a 36% pre-market stock drop. The trial confirmed safety signals including no meaningful rise in suicidal ideation. The results mark regulatory progress but highlight market hesitancy regarding effect size and commercial outlook.