A pilot study of lithium carbonate plus divalproex sodium for the continuation and maintenance treatment of patients with bipolar I disorder.

BACKGROUND

This pilot study compared the efficacy of lithium plus divalproex sodium with the efficacy of lithium alone for the continuation and maintenance treatment of patients with bipolar I disorder.

METHOD

Twelve patients with bipolar I disorder as defined by the DSM-III-R were recruited and followed prospectively for up to 1 year. Each subject received lithium at serum levels of 0.8 to 1.0 mmol/L and a management/education session weekly or every 2 weeks. By random assignment, subjects received either divalproex sodium or placebo in conjunction with lithium. Divalproex sodium was adjusted to achieve a serum concentration of 50 to 125 micrograms/mL. Adjunctive medications were used on an as needed basis to treat psychosis, depression, and anxiety. The course of illness was monitored through use of the Longitudinal Interval Follow-up Examination.

RESULTS

Subjects treated with the combination of lithium and divalproex were significantly less likely to suffer a relapse or recurrence (p = .014), but were significantly more likely to suffer at least one moderate or severe adverse side effect (p = .041). There was no significant difference between groups in the use of adjunctive medication.

CONCLUSION

These results provide preliminary evidence of the risks and benefits of combining lithium with divalproex sodium for the continuation and maintenance treatment of bipolar I disorder.