The structure of depressive symptoms and characteristics and their relation to overall severity in major depressive disorder.

Although many investigators have examined symptoms of major depressive disorder (MDD), the multivariate relations among these features of depression and their relative associations with overall severity of depression are not well understood. The present study is the first to examine the underlying factor structure of depression across a broad set of constructs and to model the multivariate association of these factors with the overall severity of depression. We conducted a large-scale factor analysis and multiple regression in a sample of participants diagnosed with MDD (N = 233) and healthy controls (N = 235). We obtained a five-factor solution composed of the following factors: (1) anxiety; (2) behavioral activation; (3) core symptoms; (4) rumination; and (5) emotional intensity. The core symptoms factor, composed primarily of DSM-5 diagnostic criteria for MDD, was the only factor that showed a consistent, significant association with overall severity of depression and functional impairment. Rumination combined with behavioral inhibition and positive and negative affect combined with each other to form coherent constructs that may be useful in examining differences among depressed individuals. These findings provide an important data-driven framework for the multidimensional symptom structure of depression and suggest several actionable ways for improving clinical assessment and treatment for individuals with MDD.