Determining remission from depression on two self-report symptom scales: a comparison of the Quick Inventory of Depressive Symptomatology and the Clinically Useful Depression Outcome Scale

Abstract

To answer fundamental questions regarding the effectiveness of treatments for depression in real-world clinical practice, it is necessary to incorporate the measurement of outcome. Self-report questionnaires are a cost-effective option to systematically, reliably, and validly evaluate clinical status because they are inexpensive in terms of professional time needed for administration, and do not require special training for administration. While there are many self-administered depression scales, only a limited number cover all of the diagnostic criteria for major depressive disorder (MDD) and have had cutoff scores derived corresponding to the Hamilton Depression Rating Scale (HAM-D) definition of remission. In the present study from the Rhode Island Methods to Improve Diagnostic Assessment and Services project, we compared 2 scales in their respective ability to identify remission as defined by the HAM-D. We administered the 17-item HAM-D to 274 depressed outpatients in ongoing treatment. The patients completed the Quick Inventory of Depressive Symptomatology (QIDS) and the Clinically Useful Depression Outcome Scale (CUDOS). Based on the cutoffs recommended by the developers of the scales to identify remission, the 2 scales performed similarly overall though the sensitivity was higher for the QIDS than the CUDOS (95.5% vs. 78.7%), whereas specificity was higher for the CUDOS than the QIDS (73.0% vs. 50.0%). On the CUDOS, the cutoff that maximized the sum of sensitivity and specificity was similar to cutoff initially derived for this purpose; however, for the QIDS, the optimal cutoff was higher than the cutoff originally derived for this purpose. In conclusion, the CUDOS and the QIDS were equally highly related to the HAM-D definition of remission. The CUDOS takes less time to complete than the QIDS and, therefore, may be preferable to use in routine clinical practice.