Comparison of two anticonvulsants in a randomized, single-blind treatment of hypomanic symptoms in patients with bipolar disorder

Objective: Oxcarbazepine was compared to divalproex to assess clinical effectiveness of a proven agent, divalproex, against a newer, less studied agent, oxcarbazepine, in the treatment of hypomania. Method: Thirty patients with bipolar disorder, currently hypomanic, were randomized to receive oxcarbazepine or divalproex as add-on or monotherapy for 8 weeks. A rater blind to treatment assignment performed all symptom ratings. Hypomania and depression were rated using the Young Mania Rating Scale (YMRS) and the Inventory of Depressive Symptoms-Clinician Version (IDS-C). Random regression models were used to assess clinical symptom scores. Results: There were no significant differences of YMRS or IDS-C scores between groups. Mean YMRS scores at baseline were 22.07 ± 5.86 and 20.53 ± 6.02 for the oxcarbazepine and the divalproex groups, respectively. Mean percent reduction from baseline to week 8 for the YMRS was 63.8% and 79.0% for oxcarbazepine and divalproex groups, respectively. Mean percent reduction from baseline to week 8 for the IDS-C was 48.7% versus 19.7% for oxcarbazepine and divalproex groups, respectively. Significant antimanic efficacy was noted for each medication. Both medications were generally well tolerated. Conclusion: In this pilot study, oxcarbazepine was as effective as divalproex in the treatment of hypomania. Further controlled trials are warranted.