The validity and reliability of the Turkish version of the bipolar depression rating scale

Introduction: Unipolar depression and bipolar depression differ in their clinical presentations, and the conventional depression rating scales fail to capture these differences. Recently, a new scale to rate the severity of depression in bipolar disorder was developed, and this study aims to evaluate the validity and reliability of this scale in a Turkish clinical sample. Methods: A total of 81 patients (30 males, 51 females) diagnosed with bipolar depression according to the DSM-IV-TR criteria at three different sites in Turkey were interviewed with the Bipolar Depression Rating Scale (BDRS), the Montgomery Asberg Depression Rating Scale, the Young Mania Rating Scale, and the Positive and Negative Syndrome Scale Depression and Excitement subscales. Internal consistency, interrater reliability and concurrent validity of the BDRS were evaluated. Results: The Turkish version of the BDRS had an acceptable internal consistency (Cronbach's alpha = 0.786). Moderate to strong correlations between the BDRS, and the MADRS (r = 0.808), and the PANSS-D (r = 0.426) were observed, and the BDRS correlated weakly to moderately with the PANSS-E (r = 0.297), and the YMRS (r = 0.368). The mixed symptom cluster score of the BDRS significantly correlated with the YMRS (r = 0.755), and the PANSS-E (r = 0.712). Exploratory factor analysis showed a three-factor solution. These factors corresponded to somatic depression, psychological depression, and mixed symptoms. Conclusions: This study shows that the Turkish version of the BDRS is a valid and reliable instrument to measure depressive symptomatology in bipolar disorder. The scale has good internal validity, strong interrater reliability, and moderate to strong correlations with other depression rating scales. (C) 2014 Elsevier Inc. All rights reserved.