Irritability is associated with anxiety and greater severity, but not bipolar spectrum features, in major depressive disorder.

OBJECTIVE: Irritability is common during major depressive episodes, but its clinical significance and overlap with symptoms of anxiety or bipolar disorder remains unclear. We examined clinical correlates of irritability in a confirmatory cohort of Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study participants with major depressive disorder (MDD).

METHOD: Logistic regression was used to identify features associated with presence of irritability on the clinician-rated Inventory of Depressive Symptomatology.

RESULTS: Of 2307 study participants, 1067(46%) reported irritability at least half the time during the preceding week; they were more likely to be female, to be younger, to experience greater depression severity and anxiety, and to report poorer quality of life, prior suicide attempts and suicidal ideation. Bipolar spectrum features were not more common among those with irritability.

CONCLUSION: Irritable depression is not a distinct subtype of MDD, but irritability is associated with greater overall severity, anxiety comorbidity and suicidality.