<p>Development of the 12-item questionnaire for quantitative assessment of depressive mixed state (DMX-12)</p>

Abstract

Background Conventional categorical criteria have limitations in assessing the prevalence and severity of depressive mixed state (DMX). Thus, we have developed a new scale for screening and quantification of DMX and examined the symptomatological structure and severity of DMX in individuals with major depressive episode (MDE). Methods Subjects were 154 patients with MDE (57 males and 97 females; age 13–83 years). Our original Japanese version of the self-administered 12-item questionnaire to assess DMX (DMX-12), together with the Quick Inventory of Depressive Symptomatology Self-Report Japanese version (QIDS-SR-J) and global assessment of functioning, were administered to each participant. The symptomatological structure of the DMX-12 was examined by exploratory factor analysis. Multiple regression analyses were used to analyze factors contributing to the DMX-12 scale. The relationships of this scale with categorical diagnoses (mixed depression by Benazzi and mixed features by DSM-5) were also investigated. Results A three-factor model of the DMX-12 was extracted from exploratory factor analysis, namely, “spontaneous instability”, “vulnerable responsiveness”, and “disruptive emotion/behavior”. Multiple regression analyses revealed that age was negatively correlated with total DMX-12 score, while bipolarity and the QIDS-SR-J score were positively correlated. A higher score on the disruptive emotion/behavior subscale was observed in patients with mixed depression and mixed features. Conclusion The DMX-12 seems to be useful for screening DMX in conjunction with conventional categorical diagnoses. Severely depressed younger subjects with potential bipolarity are more likely to develop DMX. The disruptive emotion/behavior subscale of the DMX-12 may be the most helpful in distinguishing patients with DMX from non-mixed patients.

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

“…Patients with substance-related/addictive disorders or neurocognitive disorders were excluded from analyses. This study used the same dataset as our previous study [16].…”

“…The DMX-12 questionnaire in Japanese was developed by us (Appendix 1) [16], according to previously reported core features for DMX such as distractibility, irritability and psychomotor agitation (inner tension and restlessness) and racing/crowded thought [3,14] as well as other prevalent mixed symptoms, e.g., mood lability, overreactivity, impulsivity, aggression and risk-taking behavior, pointed out from previous researches [7,17]. This scale was also translated into English and was again back-translated into Japanese by two native speakers for both English and Japanese, followed by confirmation from all the authors (Appendix 2) [16]. We used the original version (in the Japanese language) in the present study.…”

“…Recently, we proposed a postulated model for depressive psychopathology structured by static/ dynamic and internalized/externalized dimensions together with its plausible treatment options and suggested the necessity of dimensional approaches to assess various types of depressive symptomatology such as melancholic depression, psychotic depression and mixed depression [3]. Thereafter, we have developed the 12-item questionnaire for screening and quantification of DMX (DMX-12), covering non-specific but frequent mixed symptoms [16].…”

“…The DMX-12 consists of 3 subscales, namely, spontaneous instability " (restlessness, distractibility, racing/crowded thought, mood lability, inner tension and impulsivity), vulnerable responsiveness " (hypersensitivity and overreactivity) and disruptive emotion/behavior " (aggression, irritability, dysphoria and risk-taking behavior) by exploratory factor analysis (Table 1) [16]. Severity of DMX assessed by the DMX-12 was positively correlated with severity of core depressive symptoms and bipolarity while it was negatively correlated with age, suggesting that severely depressed younger subjects with potential bipolarity are more likely to develop DMX [16].…”

“…In the present study, we aimed to investigate the relationship of our dimensional scale for DMX (DMX-12) [16] with conventional categorical diagnoses of MD [12][13][14] and MF [6].…”