Yale-Brown Obsessive Compulsive Scale (Y-BOCS)

No. The Y-BOCS is strictly a clinician-administered instrument. A trained rater must conduct the interview, probe for clarification, and assign scores based on clinical judgment. Patient self-report versions do not exist and would compromise validity. For self-report OCD severity, use the OCI-R (Obsessive-Compulsive Inventory—Revised, 18 items) or the DOCS (Dimensional Obsessive-Compulsive Scale, 20 items).

A reduction of ≥4 points (10% of the scale range) is statistically significant and reflects meaningful clinical change. For treatment response in trials, a ≥25% reduction from baseline is often used as the threshold. For example, a patient with baseline Y-BOCS = 28 (severe) would need to drop to ≤21 (25% reduction) to be classified as a responder. Individual item changes, particularly on items 1–3 (obsession time, interference, distress), often precede compulsion improvement.

Administration typically requires 15–20 minutes for experienced raters with straightforward OCD presentations; complex cases or pure-O may take 30 minutes. In clinical practice, repeat administration at weeks 2, 4, 8, and 12 during acute treatment is standard. In maintenance or long-term follow-up, monthly to quarterly reassessment is typical. Training in proper administration is essential; the Obsessive Compulsive Foundation and IOCDF offer certified rater training.

The same 0–40 scale and severity bands (subclinical, mild, moderate, severe, extreme) apply to both adolescents and adults. However, the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) is specifically designed for ages 6–17 and has been normed separately; it is preferred for this age group. For late adolescents (17+), the adult Y-BOCS may be used if symptom presentation is adult-typical, but clinical judgment is advised.

No. The Y-BOCS measures severity within OCD but does not diagnose OCD or differentiate it from other conditions. A structured diagnostic interview (SCID, MINI, or clinical assessment) must be conducted first. The scale can be adapted or used for related conditions (trichotillomania, skin picking) where obsessive-compulsive features are present, but it is not validated for these; use condition-specific severity scales instead.

Y-BOCS severity scores correlate moderately with functional impairment and quality-of-life measures (r = 0.40–0.60) but do not directly measure either. A patient with Y-BOCS = 20 (moderate) may have vastly different functional outcomes depending on insight, coping, social support, and comorbidities. Administer concurrent measures (e.g., WHODAS, SF-36, Sheehan Disability Scale) to capture functional and quality-of-life impact alongside Y-BOCS severity.