Validation of the Turkish Yale-Brown Obsessive-Compulsive Scale and Self-Report version: psychometric evidence from clinical and non-clinical populations

Background Obsessive – compulsive disorder (OCD) is a chronic condition that disrupts functioning and quality of life. The Yale – Brown Obsessive – Compulsive Scale (Y-BOCS; clinician-administered) and its Self-Report version (Y-BOCS-SR) are recognised gold standards for assessing OCD severity. Previous Turkish adaptations have been partial, limited by small samples or by validating only one format. This study provides the first comprehensive Turkish validation of both instruments.Methods The sample comprised 950 adults: 158 with DSM-5-TR – diagnosed OCD and 792 non-clinical adults. Translation followed a multi-phase process involving clinicians and a linguistics expert. Participants completed the Turkish Y-BOCS, Y-BOCS-SR, and additional OCD measures (OCI-R, VOCI, PI-R).Results The clinician-administered Turkish Y-BOCS demonstrated excellent reliability (α = 0.91; ICC = 0.88) and strong psychometric validity, including a stable two-factor structure distinguishing obsessions and compulsions. The self-report version showed comparably high internal consistency (α = 0.90) and strong convergence with the clinician-administered scale. Convergent and criterion validity were robust, with high sensitivity and specificity. Cross-cultural comparisons further supported consistency and generalisability.Conclusions This study establishes both the clinician-administered and self-report Turkish Y-BOCS as reliable, valid, and culturally sensitive tools for assessing OCD severity in clinical and research contexts.