Yale-Brown Obsessive Compulsive Scale (Y-BOCS)
The standard clinician-administered scale for measuring the severity of obsessive-compulsive disorder.
By Claire White
- Clinician-administered in a semi-structured interview; approximately 20 to 30 minutes.
- 10 items: 5 for obsessions (time, interference, distress, resistance, control) and 5 for compulsions (same dimensions).
- Obsessions score 0–20, compulsions score 0–20, total 0–40 (higher = more severe).
- Cut-offs: 8–15 mild, 16–23 moderate, 24–31 severe, 32–40 extreme.
- Reference information. It does not diagnose.
What it measures
The Y-BOCS asks about the time spent on, interference from, distress caused by, resistance to, and perceived control over obsessions and compulsions separately. Items are scored 0–4 each. An initial symptom checklist (not scored) identifies the type of obsessions and compulsions present. The Y-BOCS rates severity, not type or diagnosis.
What the result tells you
Total scores (0–40) classify OCD severity. A reduction of 35% or more in Y-BOCS score is generally considered a clinical response. The scale is the primary efficacy endpoint in OCD treatment trials (CBT and pharmacotherapy). It is sensitive to change and widely accepted by regulatory agencies.
Evidence, psychometrics and provenance
Psychometrics
- Inter-rater reliability
- ICC ≈ 0.98
- Internal consistency
- Cronbach α = 0.88