Yale-Brown Obsessive Compulsive Scale (Y-BOCS) Scoring Interpretation
The Y-BOCS is a 10-item clinician-rated scale with total scores ranging from 0 to 40, where each item is scored 0 (no symptoms) to 4 (extreme symptoms), with obsessions and compulsions each contributing up to 20 points to the total score. 1, 2
Score Ranges and Severity Classification
The Y-BOCS quantifies OCD symptom severity based on time spent on obsessions/compulsions, distress levels, and degree of functional interference 1, 3:
- 0-7: Subclinical symptoms
- 8-15: Mild OCD
- 16-23: Moderate OCD
- 24-31: Severe OCD
- 32-40: Extreme OCD
For severe, treatment-refractory OCD requiring consideration of neurosurgical interventions, a threshold score of ≥28 is required (or ≥14 if only obsessions or only compulsions are present). 1
Diagnostic Utility
A cut-off score of 13 on the Y-BOCS-II (Second Edition) demonstrates optimal discriminatory ability for OCD diagnosis, with sensitivity of 85-90% and specificity of 94-97%. 4 This threshold effectively distinguishes OCD patients from both healthy controls and patients with other mood and anxiety disorders 4.
The scale's content-independent design allows it to measure severity regardless of the specific type of obsessions or compulsions present, making it applicable across all OCD presentations including relationship-themed obsessions 3, 2.
Clinical Application for Treatment Monitoring
A clinically meaningful treatment response is defined as a ≥35% reduction from baseline Y-BOCS scores. 3, 5
For example, case studies demonstrate dramatic symptom reduction tracking: a patient with Sexual Orientation OCD showed Y-BOCS scores decreasing from 24 (severe range) at intake to 3 (subclinical) post-treatment following exposure and response prevention therapy 1.
Administration Requirements
The Y-BOCS is a semi-structured clinician-rated interview, not a self-report measure 2, 6:
- Ratings are based on both patient report and clinician observation during the interview 6
- Clinicians must be trained in recognizing nuanced OCD presentations to ensure accurate scoring 3
- The scale should be administered alongside thorough clinical assessment of specific obsession/compulsion content, as the Y-BOCS itself is content-independent 3
Psychometric Properties
The Y-BOCS demonstrates excellent reliability and validity 2, 7, 8:
- Interrater reliability: Intraclass correlations >0.85-0.99 7, 8
- Test-retest reliability: Correlations 0.64-0.94 7, 8
- Internal consistency: Cronbach's α = 0.86-0.96 7, 8, 4
- Factor structure: Two-factor solution corresponding to Obsession and Compulsion Severity subscales 7, 4
Critical Clinical Pitfalls
Avoidance behaviors may lead to underestimation of symptom severity on the Y-BOCS. 1 Patients who extensively avoid triggering situations may spend less time on active obsessions/compulsions, artificially lowering scores despite severe functional impairment 1.
Family accommodation assessment must accompany Y-BOCS administration, as relationship partners or family members may inadvertently reinforce symptoms through reassurance-giving or participation in rituals, which affects the accuracy of interference ratings 3.
The Y-BOCS-II (Second Edition) addresses limitations of the original version by integrating avoidance into severity scoring and modifying item content based on improved phenomenological understanding of OCD 7, 8.