Abstract
The use of Patient-reported Outcomes (PROs) as secondary endpoints in the development of new antidepressants has grown in recent years. The objective of this study was to assess the psychometric properties of the 9-item, patient-administered version of the Montgomery-Åsberg Depression Rating Scale (MADRS-S). Data from a multicentre, double-blind, 8-week, randomised controlled trial of 278 outpatients diagnosed with Major Depressive Disorder were used to evaluate the validity, reliability and sensitivity to change of the MADRS-S using psychometric methods. A Receiver Operating Characteristic (ROC) curve was plotted to identify the most appropriate threshold to define perceived remission. No missing values were found at the item level, indicating good acceptability of the scale. The construct validity was satisfactory: all items contributed to a common underlying concept, as expected. The correlation between MADRS-S and physicians' MADRS was moderate (r = 0.54, p < 0.001) indicating that MADRS-S is complementary rather than redundant to the MADRS. Cronbach's alpha was 0.84, and the stability over time of the scale, estimated on a sub-sample of patients whose health status did not change during the first week of the study, was good (intraclass correlation coefficient of 0.78). MADRS-S sensitivity to change was shown. Using a threshold value of 5, the definition of "perceived remission" reached a sensitivity of 82% and a specificity of 75%. Taking account of patient's perceptions of the severity of their own symptoms along with the psychometric properties of the MADRS-S enable its use for evaluative purposes in the development of new antidepressant drugs.