Clinical indicators for the use of antidepressants in the treatment of bipolar I depression

Objectives: Current guidelines provide little practical information on the clinical characteristics of bipolar I patients who are likely to benefit from the combination of a mood stabilizer and an antidepressant. Rather, guidelines simply state that an adjunctive antidepressant is recommended in cases of 'severe' depression. Our objective was to evaluate the clinical and demographic differences between patients who remitted on a mood stabilizer alone and patients who subsequently required an adjunctive antidepressant to achieve stabilization. Methods: We retrospectively compared the pharmacological treatment strategies of 39 patients with bipolar I disorder who were in a current depressive episode. Patients who did not respond to mood stabilizer monotherapy were prescribed an adjunctive antidepressant. We evaluated the clinical differences at baseline and week 1, 2 and 3 of treatment between patients stabilizing on a mood stabilizer alone and patients that did not remit until they subsequently received an adjunctive antidepressant. Results: Patients who required an adjunctive antidepressant had significantly higher total Hamilton Depression Rating (HRS-D) scores at week 1, 2 and 3 of treatment, but not at baseline. Patients who remitted on mood stabilizer monotherapy were more likely to be married, achieved stabilization in less time, presented with higher Young Mania Rating Scale (YMRS) scores, and experienced the previous episode of depression more recently than patients who required an antidepressant. Conclusions: Our findings suggest that rapid improvement after achieving a therapeutic dose of a mood stabilizer is clinically significant and represents a surrogate endpoint in the treatment of bipolar I depression. Larger, prospective, and controlled studies are needed to verify our results and to identify additional indicators for a mood stabilizer and antidepressant combination treatment strategy.