Measurement-based Treatment of Residual Symptoms Using Clinically Useful Depression Outcome Scale: Korean Validation Study

Objective: This study was aimed at evaluating the diagnostic validity of the Korean version of the Clinically Useful Depression Outcome Scale (CUDOS) with varying follow-up in a typical clinical setting in multiple centers. Methods: In total, 891 psychiatric outpatients were enrolled at the time of their intake appointment. Current diagnostic character-istics were examined using the Structured Clinical Interview for DSM-IV (41% major depressive disorder). The CUDOS was meas-ured and compared with three clinician rating scales and four self-report scales. Results: The CUDOS showed excellent results for internal consistency (Cronbach’s α ,0.91), test-retest reliability (patients at intake, r =0.81; depressed patients in ongoing treatment, r =0.89), and convergent and discriminant validity (measures of depres-sion, r =0.80; measures of anxiety and somatization, r =0.42). The CUDOS had a high ability to discriminate between different levels of depression severity based on the rating of Clinical Global Impression for depression severity and the diagnostic classi-fication of major depression, minor depression, and non-depression. The ability of the CUDOS to identify patients with major depression was high (area under the receiver operating characteristic curve=0.867). A score of 20 as the optimal cutoff point was suggested when screening for major depression using the CUDOS (sensitivity=89.9%, specificity=69.5%). The CUDOS was sensitive to change after antidepressant treatment: patients with greater improvement showed a greater decrease in CUDOS scores ( p ＜0.001). Conclusion: The results of this multi-site outpatient study found that the Korean version of the CUDOS is a very useful measure-ment for research and for clinical practice.