Irritable mood in adult major depressive disorder: results from the world mental health surveys.

BACKGROUND: Although irritability is a core symptom of DSM-IV major depressive disorder (MDD) for youth but not adults, clinical studies find comparable rates of irritability between nonbipolar depressed adults and youth. Including irritability as a core symptom of adult MDD would allow detection of depression-equivalent syndromes with primary irritability hypothesized to be more common among males than females. We carried out a preliminary examination of this issue using cross-national community-based survey data from 21 countries in the World Mental Health (WMH) Surveys (n = 110,729).
METHODS: The assessment of MDD in the WHO Composite International Diagnostic Interview includes one question about persistent irritability. We examined two expansions of the definition of MDD involving this question: (1) cases with dysphoria and/or anhedonia and exactly four of nine Criterion A symptoms plus irritability; and (2) cases with two or more weeks of irritability plus four or more other Criterion A MDD symptoms in the absence of dysphoria or anhedonia.
RESULTS: Adding irritability as a tenth Criterion A symptom increased lifetime prevalence by 0.4% (from 11.2 to 11.6%). Adding episodes of persistent irritability increased prevalence by an additional 0.2%. Proportional prevalence increases were significantly higher, but nonetheless small, among males compared to females. Rates of severe role impairment were significantly lower among respondents with this irritable depression who did not meet conventional DSM-IV criteria than those with DSM-IV MDD.
CONCLUSION: Although limited by the superficial assessment in this single question on irritability, results do not support expanding adult MDD criteria to include irritable mood.