Challenges in the management of bipolar depression.

Bipolar depression has started to receive more attention in clinical trials only relatively recently, despite the fact that patients spend more time in the depressed phase than in the manic phase of bipolar disorder. The diagnosis and management of bipolar depression are challenging, and many patients are undiagnosed or misdiagnosed due to symptom similarities with unipolar depression or other illnesses and/or comorbidities. Untreated or inappropriately treated bipolar depression adds to the burden of illness and is associated with a greater risk of suicide. Treatment options include lithium, lamotrigine, atypical antipsychotics, and traditional antidepressants, such as the selective serotonin reuptake inhibitors. However, traditional antidepressants are recommended with caution due to their potential risk of switching patients into mania. Some atypical antipsychotics have shown efficacy in bipolar depression, although longer-term studies are warranted. The choice of treatment for different subgroups of patients with bipolar depression, including those with comorbid anxiety, may vary and also needs further study. Other important issues that require further investigation include the recognition of the core features of bipolar depression and the threshold symptoms for treatment, as well as the optimal treatment choices for monotherapy or combination therapy, and acute versus long-term management of bipolar depression.