Newer anticonvulsants in the treatment of bipolar disorder.

The anticonvulsants valproate and carbamazepine have efficacy in treating acute mania, but their efficacy in treating acute bipolar depression and preventing mood episodes remains uncertain. Despite this, and given their utility and widespread use, both are widely accepted as standard treatments for bipolar disorder. All the newer anticonvulsants that have become available during the last decade have been or are being assessed to determine their efficacy in the treatment of various phases of bipolar disorder. Among the newer anticonvulsants, some appear to have efficacy in treating core bipolar symptoms, while others have efficacy in treating psychiatric comorbidity such as substance abuse or an anxiety disorder. Lamotrigine is the most widely studied and is effective in treating and preventing bipolar depression, and it is the only anticonvulsant approved by the U.S. Food and Drug Administration as a maintenance treatment for bipolar disorder. Other newer anticonvulsants, levetiracetam, oxcarbazepine, phenytoin, and zonisamide offer promise, but further studies are required before they can be recommended for routine use to treat bipolar disorder. Gabapentin and topiramate do not appear to have efficacy in treating acute mania, but their utility in bipolar depression and prevention of mood episodes has not been studied in double-blind trials. Pregabalin has utility in treating generalized anxiety disorder, but it has not been studied in bipolar disorder. Given the success of lamotrigine in treating bipolar disorder, further double-blind controlled trials of the newer anticonvulsants in treating bipolar disorder are warranted. This article summarizes current evidence from trials of anticonvulsants in bipolar disorder and makes recommendations for their clinical use.