Bipolar disorders, particularly bipolar spectrum disorders, frequently go unrecognized and undiagnosed by clinicians and thus remain untreated or inappropriately treated. Although the symptoms of bipolar I disorder are widely acknowledged and recognized among clinicians, epidemiology sampling studies over the past several years have found that bipolar II disorder and bipolar spectrum disorders are likely to be more prevalent and more challenging to diagnose, particularly as depressive presentations are far more common in these groups. Bipolar disorder is associated with increased morbidity and mortality, as well as higher healthcare costs, but it is unclear how much of the consequences of bipolar disorder are unrecognized in the face of poor recognition of bipolar II and bipolar spectrum disorders. This article addresses challenges in diagnosing and treating bipolar disorder in the face of a depressive episode, and offers guidelines for recognizing and appropriately managing these patients. Studies with the newer anticonvulsant mood stabilizer lamotrigine have shown antidepressant effects in bipolar disorder, and may fill an unmet need for treatment options in patients who present with depression in the context of bipolar disorder.