Bowden CL, Singh V, Weisler R, Thompson P, Chang X, Quinones M, Mintz J. Lamotrigine vs. lamotrigine plus divalproex in randomized, placebo-controlled maintenance treatment for bipolar depression.
Objective: To compare the maintenance efficacy of lamotrigine (Lam) to combination therapy of Lam + divalproex ER (Div) in recently depressed patients with bipolar disorder (BD).
Method: We randomized 86 BD I or II patients in a major depressive episode to 8 months of double-blind treatment with Lam + placebo or Lam + Div. To be eligible for randomization, patients had to achieve control of both depressive and manic symptoms during an open phase that included both Lam and Div.
Results: Time to depressive episode did not differ significantly by Kaplan–Maier survival analysis (χ2 = 1.82, df = 1, P = 0.18). However, several secondary outcomes did show significant differences. The proportion of Lam + placebo patients who had at least one Montgomery–Asberg Depression Rating Scale (MADRS) score ≥15 during the maintenance phase was 67% (30/45) compared with 44% (18/41) for the Lam + Div group (χ2 = 4.51, P = 0.03). Among BD I patients assigned to Lam + placebo, 71.4% (25/35) had at least one visit with MADRS score ≥15 compared with 36.7% (11/30) among Lam + Div patients (χ2 = 7.89, df = 1, P = 0.005).
Conclusion: Lam + Div generally provided greater maintenance efficacy than Lam alone for depressive indices in recently depressed BD patients.