Diagnostic Discrimination of Patients with Different OCD Main Symptom Domains from each Other and from Anxious and Depressive Controls

The extent to which the subscales of multidimensional OCD measures accurately distinguish patients with specific OCD main symptom domains from controls at different cutscores has not yet been examined. Diagnostic accuracy of OCD measures usually is determined by comparing the total scores of heterogeneous OCD samples and controls and therefore may underestimate the measures’ discrimination potential. In the current study, subtype-specific diagnostic accuracy and criterion-related validity of the Obsessive-Compulsive Inventory-Revised (OCI-R) subscales were examined in 327 patients with OCD, anxiety, and/or depressive disorders. All subscales demonstrated good to excellent criterion-related validity and diagnostic accuracy for distinguishing patients with specific OCD main symptom domains from controls. As expected, the single OCI-R subscales lead to more accurate diagnostic decisions than the total scale. Thus, the subscale-specific cutscores significantly improve the OCI-R’s utility for subtype-specific treatment planning and outcome measurement. Furthermore, an alternative classification algorithm distinguishing patients with OCD from controls based on subscale cutscores leads to a better sensitivity, but also to a lower specificity than discrimination based on the total scale cutscore.