Acute efficacy of divalproex sodium versus placebo in mood stabilizer-naive bipolar I or II depression: a double-blind, randomized, placebo-controlled trial.

OBJECTIVE

To conduct an exploratory evaluation of the acute efficacy of extended-release divalproex sodium compared to placebo in patients with bipolar I or II depression.

METHOD: Outpatients aged 18-70 years with mood stabilizer-naive bipolar I or II disorder experiencing a major depressive episode (DSM-IV) were randomly assigned to 6 weeks of divalproex sodium monotherapy or placebo. The primary outcome measure was mean change from baseline to week 6 on the Montgomery-Åsberg Depression Rating Scale (MADRS) total score. Secondary outcomes included rates of response and remission, changes in the Clinical Global Impressions-Bipolar (CGI-BP) Severity of Illness scores, and changes in anxiety symptoms as measured by the Hamilton Anxiety Rating Scale. The study was conducted between 2003 and 2007.

RESULTS

Fifty-four subjects with bipolar I (n = 20) or bipolar II (n = 34) disorder were randomly assigned to divalproex or placebo; 67% (36 of 54) met DSM-IV criteria for rapid cycling. Divalproex treatment produced statistically significant improvement in MADRS scores compared with placebo from week 3 onward. The proportions of patients meeting response criteria were 38.5% (10 of 26) in the divalproex group versus 10.7% (3 of 28) for the placebo group (P = .017). The proportions of patients meeting remission criteria were 23.1% (6 of 26) for divalproex versus 10.7% (3 of 28) for placebo (P = .208). Subgroup analysis revealed no separation between divalproex and placebo for those with bipolar II diagnoses. Nausea, increased appetite, diarrhea, dry mouth, and cramps were the most common side effects.

CONCLUSIONS

These data suggest that divalproex sodium is efficacious and reasonably well tolerated in the acute treatment of mood stabilizer-naive patients with bipolar depression, particularly for those with rapid-cycling type I presentations, and that confirmatory large-scale studies are indicated.

TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT00194116.