GlossaryY-BOCS

Y-BOCS

Yale-Brown Obsessive Compulsive Scale — the primary validated outcome measure used in OCD clinical research. Assesses symptom severity across obsessions and compulsions on a 0–40 scale (0 = no symptoms, 40 = extreme). A reduction of 35% or more from baseline is generally considered clinically significant. Used in all psilocybin OCD trials as the key efficacy endpoint. In the 2006 University of Arizona pilot study, participants showed 23–100% Y-BOCS reductions across dosing sessions. (Moreno et al., Journal of Clinical Psychiatry, 2006)

Full Explanation

Y-BOCS (Yale-Brown Obsessive Compulsive Scale) is the primary validated outcome measure used in OCD clinical research. It assesses symptom severity across obsessions and compulsions on a 0–40 scale (0 = no symptoms, 40 = extreme). A reduction of 35% or more from baseline is generally considered clinically significant. Used in all psilocybin OCD trials as the key efficacy endpoint. In the 2006 University of Arizona pilot study, participants showed 23–100% Y-BOCS reductions across dosing sessions. (Moreno et al., Journal of Clinical Psychiatry, 2006)

See: OCD (/conditions/ocd).

Why It Matters

When reading psilocybin OCD studies, Y-BOCS is the main outcome — a 35% or greater drop indicates clinically meaningful improvement.

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