Although rapid-cycling bipolar disorder has been linked to the use of antidepressants, these treatments may still have a role in the management of patients with bipolar depression, said Stephen V. Sobel, MD, clinical instructor at the University of California, San Diego School of Medicine, in a presentation at the U.S. Psychiatric and Mental Health Congress in Las Vegas. Patients with bipolar disorder spend most of their time in depression, and antidepressants can alleviate these symptoms, said Sobel. “That’s why it’s so tempting to treat these patients with an antidepressant. But it’s important to be familiar with recent studies on the development of rapid-cycling bipolar disorder and to weigh the risks and benefits,” he said.

The use of antidepressants may increase a patient’s risk of rapid-cycling bipolar disorder. The Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) included 1742 patients treated with a variety of approved medications for bipolar I and bipolar II disorder, and 32% reported having rapid-cycling at baseline. After 2 years of treatment, 5% still had rapid-cycling bipolar disorder. Those who were treated with an antidepressant were 3.8 times more likely to have rapid-cycling bipolar disorder.1

Based on his clinical experience, Sobel has seen positive results when treating patients who have bipolar depression with antidepressants as adjunctive therapy. But physicians should also consider that antidepressants have been shown to be ineffective as adjunctive therapy. In another STEP-BD study, patients with bipolar depression were treated for up to 26 weeks with a mood stabilizer and adjunctive antidepressant therapy or a mood stabilizer and placebo. Results showed that in patients with bipolar depression who were treated with a mood stabilizer, the addition of an antidepressant was no more effective than the addition of a placebo.2

Adjunctive therapy with antidepressants has also been shown to cause an increase in the incidence of symptoms of hypomania or mania. In a study with a 10-week acute phase and a 1-year continuation phase, 150 patients with bipolar I or bipolar II disorder were treated with an antidepressant (bupropion, sertraline, or venlafaxine) in addition to a mood stabilizer. In the acute phase, 11.4% patients switched to hypomania and 7.9% switched to mania. In the continuation phase, 21.8% switched to hypomania and 14.9% switched to mania. In all patients, only 23% experienced a sustained response to the antidepressants.3

Guidelines state that patients with bipolar depression who are treated with an antidepressant should discontinue therapy within 3 to 6 months after achieving remission. However, discontinuation of antidepressants has been shown to cause depressive relapse in these patients,4 said Sobel. He suggests that physicians should use their discretion to determine how best to treat their patients while also keeping the results of these studies in mind.