Current irritability associated with hastened depressive recurrence and delayed depressive recovery in bipolar disorder

BACKGROUND Current irritability is associated with greater retrospective and current bipolar disorder (BD) illness severity; less is known about prospective longitudinal implications of current irritability. We examined relationships between current irritability and depressive recurrence and recovery in BD. METHODS Outpatients referred to the Stanford BD Clinic during 2000-2011 were assessed with the Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation at baseline, and with the Clinical Monitoring Form during follow-up during up to 2 years of naturalistic treatment. Prevalence and clinical correlates of any current irritability in depressed and recovered (euthymic ≥8 weeks) BD patients were assessed. Kaplan-Meier analyses (Log-Rank tests) assessed relationships between current irritability and longitudinal depressive severity, with Cox Proportional Hazard analyses assessing potential mediators. RESULTS Recovered BD outpatients with vs. without current irritability had significantly higher rates of 13/19 (68.4 %) other baseline unfavorable illness characteristics/current mood symptoms and hastened depressive recurrence (Log-Rank p = 0.020), driven by lifetime history of anxiety disorder and prior year rapid cycling, and attenuated by history of psychosis. Depressed BD outpatients with vs. without current irritability had significantly higher rates of 7/19 (36.8 %) other unfavorable illness characteristics/current mood symptoms and delayed depressive recovery (Log-Rank p = 0.034), NOT mediated by any assessed parameter. LIMITATIONS Limited generalizability beyond our predominately white, female, educated, insured American BD specialty clinic sample. CONCLUSIONS Current irritability was associated with hastened depressive recurrence and delayed depressive recovery in BD. Treatment studies targeting irritability may yield strategies to mitigate increased longitudinal depressive burden.