Bipolar disorders and the effectiveness of novel anticonvulsants.

The discovery that valproic acid is helpful in the management of patients with rapid-cycling bipolar disorder led to an explosion of research culminating in the third-generation anticonvulsants. Refractory depressive phases are frequent in bipolar disorders. No studies to date have shown that gabapentin is effective in bipolar mania or hypomania. Lamotrigine may have a role in treating bipolar depressive episodes, but it is not a particularly effective antimanic agent. Topiramate has shown encouraging results in both depressed and manic bipolar patients, and it may also promote weight loss. The new anticonvulsants are promising agents for the treatment of bipolar disorders, but they are heterogeneous with regard to their efficacy, target symptoms, and adverse event profiles.