Functional impairment in patients with major depressive disorder and comorbid anxiety disorder

To analyze the potential for different aspects of anxiety to modify the effect of impaired functioning in major depressive disorder (MDD).

Participants (n = 1226) were psychiatric outpatients with MDD. A cross-sectional, multicentre, nationwide study was designed. The 12-item version of the World Health Organization Disability Assessment Schedule II was used to assess functional limitation. Anxiety was measured using the Hamilton Anxiety Rating Scale and the State-Trait Anxiety Inventory (STAI). Depression severity was measured using the Quick Inventory of Depressive Symptomatology.

About 43.1% of patients had a comorbid MDD and anxiety disorder. Poorer functioning correlated significantly with severity of depression (Pearson r = 0.78, P = 0.001), severity of anxiety (r = 0.65, P = 0.001), and higher anxiety trait scores (r = 0.40, P = 0.001), but not significantly with STAI-State scores (r = 0.03, P = 0.26). The overall regression model was significant and explained 66% of the functioning variability in patients with MDD, mostly attributable to depression severity. Results indicate that anxiety has a moderate impact on functioning impairment in patients with MDD.

Our findings suggest that MDD and anxiety severity appear to be associated significantly with impaired functioning in patients with MDD but explains only a moderate proportion of variance.