Maintenance therapies for classic and other forms of bipolar disorder.

The progressive, episodic and chronic nature of bipolar disorder dictates the need for lifelong pharmacological maintenance treatment in the majority of patients. Prophylaxis should be considered after a single episode of severe mania or after more than one episode of hypomania in bipolar II disorder, although some clinicians now consider an episode of either sufficient to warrant maintenance therapy. Lithium is efficacious as maintenance therapy, but is not as highly effective as early studies initially suggested (abrupt discontinuation of lithium probably increased placebo relapse figures). Rates of premature discontinuation of lithium are high. Divalproex sodium is used frequently in the USA and Canada for long-term treatment for bipolar disorder but an insufficient number of controlled trials have been published to assess adequately its role. Carbamazepine is also employed in maintenance treatment. Randomized studies indicate it is superior to placebo but somewhat less effective than lithium. Augmentation of any of these drugs with another mood stabilizer, an antipsychotic, or electroconvulsive therapy appears to be effective, although there are few controlled studies. Design issues that need consideration in order to achieve meaningful data are discussed. A severe manifestation of bipolar disorder is rapid cycling. It is often induced by antidepressants, although this association frequently goes unrecognized. Patients with a rapid cycling course of illness are difficult to treat effectively. Although rapid cycling is often associated with poor response to lithium, there have been no randomized, controlled treatment studies. Based on open studies and expert panel recommendations, the International Exchange on Bipolar Disorder (IEBD) recommended initial treatment with divalproex sodium, with subsequent addition of other mood stabilizers, antipsychotics or thyroid supplementation as necessary. Combination treatments are frequently required for optimal response in these patients.