Background: The intent of this study was to compare the efficacy and safety of divalproex sodium and placebo in the treatment of women with borderline personality disorder and comorbid bipolar II disorder.

Method: We conducted a placebo-controlled double-blind study of divalproex sodium in 30 female subjects aged 18 to 40 years who met Revised Diagnostic Interview for Borderlines and DSM-IV criteria for borderline personality disorder and DSM-IV criteria for bipolar II disorder. Subjects were randomly assigned to divalproex sodium or placebo in a 2:1 manner. Treatment duration was 6 months. Primary outcome measures were changes on the interpersonal sensitivity, anger/hostility, and depression scales of the Symptom Checklist 90 (SCL-90) as well as the total score of the modified Overt Aggression Scale (MOAS).

Results: Twenty subjects were randomly assigned to divalproex sodium; 10 subjects to placebo. Using a last-observation-carried-forward paradigm and controlling for baseline severity, divalproex sodium proved to be superior to placebo in diminishing interpersonal sensitivity and anger/hostility as measured by the SCL-90 as well as overall aggression as measured by the MOAS. Adverse effects were infrequent.

Conclusion: The results of this study suggest that divalproex sodium may be a safe and effective agent in the treatment of women with criteria-defined borderline personality disorder and comorbid bipolar II disorder, significantly decreasing their irritability and anger, the tempestuousness of their relationships, and their impulsive aggressiveness.