Anticonvulsants in bipolar disorders: current research and practice and future directions

Objectives: To determine the clinical effectiveness of drugs with anticonvulsant properties for interventions in persons with bipolar disorder and to place these findings in the context of clinicians' practices and their implications for future research to more effectively manage bipolar disorders. Methods: Major electronic databases were searched up to February 2009 for clinical trial data, both original studies and reviews, on drugs with anticonvulsant properties studied for bipolar disorders. Results: Valproate, principally as divalproex, has strong evidence for effectiveness in mania, moderately strong evidence for benefits in prophylaxis of recovered states, and recent proof-of-concept evidence for benefits in bipolar depression. Lamotrigine has strong evidence for evidence for effectiveness in maintenance treatment of bipolar disorder, principally for benefits in depressive states. Lamotrigine has been established as ineffective in mania and has lacked efficacy in acute bipolar depression in most randomized trials. Carbamazepine has strong evidence for effectiveness in mania, but lacks adequate studies in other aspects of bipolar disorder treatment. Its adverse effect profile and pharmacokinetic interference with a wide range of drugs, including many employed in bipolar disorder, warrants limitation of use to patients who have responded inadequately to other regimens. Conclusions: Three drugs, valproate, lamotrigine, and carbamazepine, have strong evidence-based support for use in clinical states of bipolar disorder. Other anticonvulsant drugs investigated in bipolar disorder either have evidence of lack of benefits in bipolar disorder or have been inadequately studied to determine possible effectiveness.