The 12-item self-rating questionnaire for depressive mixed state (DMX-12) in relation to categorical diagnoses of mixed depression and mixed features

Abstract

Purpose: This study aimed to investigate the relationship of the newly developed 12-item dimensional scale of depressive mixed state (DMX-12) with categorical diagnoses of mixed depression (MD) defined by Benazzi in 2008 and mixed features (MF) as a specifier for depressive and bipolar disorders by DSM-5 in 2013. Methods: The DMX-12 questionnaire was administered to 154 patients (57males and 97 females; 13-83 years) with major depressive episode (MDE) to quantify DMX symptoms. Receiver operating characteristic (ROC) curves were applied to examine the relationship between the DMX-12 and MD or MF. Results: Among 154 patients, 28 cases (18.2%) showed MD while 7 cases (4.5%) showed MF. Selected 6 symptoms with AUC values more than 0.6 for ROC curves differentiating both MD and MF were overreactivity, inner tension, racing/crowded thought, impulsivity, dysphoria and risk-taking behavior. The AUC of ROC curve using the sum of these 6 symptoms scores was higher (.716 for MD and .761 for MF) than those using total score (.670 for MD and .704 for MF) and disruptive emotion/behavior subscale score (.684 for MD and .714 for MF) of the DMX-12. When the cutoff value in common for both MD and MF was set at ≥14, the sensitivity and negative predictive value for prediction of MD and MF were .750 and .920 for MD and .857 and .989 for MF, respectively. Discussion: The selected 6 symptoms of the DMX-12 may be useful for sensitive screening and negative check of clinically relevant DMX with considerable severity in patients with MDE.