Convergent and discriminant validity of the Yale-Brown Obsessive- Compulsive Scale Symptom Checklist

Background: The factor structure of the Yale-Brown Obsessive-Compulsive Scale Symptom Checklist (Y-BOCS-SC) has been well established, but its convergent and divergent reliability have yet to be studied. Methods: Fifty-six obsessive-compulsive disorder (OCD) patients were administered the clinician-administered Y-BOCS-SC and Hamilton Rating Scale for Depression (HRSD), together with the self-administered Maudsley Obsessive Compulsive Inventory (MOCI), Padua Inventory (PI), State-Trait Anxiety Inventory (STAI), and Beck Depression Inventory (BDI). Results: Overall, the correspondence between the Y-BOCS-SC and self-administered measures of OCD symptoms was poor to moderate. Its convergent validity was adequate for its washing dimension but poor for its other dimensions. The discriminant validity of the Y-BOCS-SC was adequate, showing little overlap with overall illness severity (total Y-BOCS) and state measures (BDI, STAI, HRSD). In contrast, self-administered OCD measures were significantly correlated with overall illness severity and state measures. Conclusions: The convergent validity of the Y-BOCS-SC was generally poor and this could only be partially explained by the incomplete coverage of some OCD symptoms in the self-administered scales. Its discriminant validity was good. Both self- and clinician-administered measures should be used in OCD research, as they seem to measure relatively non-overlapping constructs. Further research on the psychometric properties of the Y-BOCS-SC is needed. Copyright © 2004 S. Karger AG, Basel.