Inpatients with major depressive disorder: Psychometric properties of the new Multidimensional Depression Scale

The New Multi-dimensional Depression Scale (NMDS) is one of the most comprehensive scales that measures depression symptoms in four domains, including emotional, cognitive, somatic, and interpersonal. This study aimed to evaluate the factor structure and psychometric properties of the NMDS in a group of Iranian inpatients with Major Depressive Disorder (MDD). At first, the scale was translated into Persian and used as part of a battery consisting of the Beck Depression Inventory-II (BDI-II), Oxford Happiness Inventory (OHI), Beck Anxiety Inventory (BAI), and Short Form Health Survey (SF-36). The battery was administered to 271 inpatients with MDD (90 men and 181 women) aged from 18 to 60 who had been referred to psychiatric hospitals in Tehran, Iran. Confirmatory factor analysis of the Persian version of the NMDS upheld its original four-factor structure. Moreover, the results showed its good internal consistency (Cronbach's alpha coefficient ranging from 0.70 for the emotional subscale to 0.83 for the interpersonal subscale). In addition, the NMDS scores were correlated with other constructs in empirically and theoretically expected ways, which provides evidence for the convergent (positive significant relationships with anxiety and cognitive and somatic-affective symptoms of depression) and divergent (negative significant relationships with happiness and mental health and physical health) validity of the scale. These findings supported the Persian version of the NMDS as a reliable and valid measure for the assessment of depression symptoms in patients with MDD.