Nosology, diagnostic challenges, and unmet needs in managing bipolar disorder

The spectrum of bipolar disorders includes the subtypes of bipolar I disorder, bipolar II disorder, cyclothymic disorder, and bipolar disorder not otherwise specified (NOS). Because depression is the most pervasive symptom of bipolar disorder, this condition is frequently misdiagnosed as unipolar major depressive disorder. As a result, patients often experience substantive delays in receiving the correct diagnosis and appropriate treatment. To help meet this important diagnostic challenge, various markers have been identified that have predictive value for a bipolar outcome, including early onset of depression, family history of bipolar disorder, atypical depressive symptoms, and the presence of psychosis. Unmet needs in the management of bipolar disorder include an enhanced diagnostic process, more options for treating bipolar depressive episodes, and safer, more tolerable medications for long-term maintenance treatment.