Previous mood state predicts response and switch rates in patients with bipolar depression

Objective: The treatment of bipolar depression is a significant clinical problem that remains understudied. The role for antidepressant (AD) agents vs. mood stabilizers has been particularly problematic to ascertain. Method: Detailed life charting data from 42 patients with 67 depressive episodes were reviewed. Response rates and rates of switch into mania were compared based on the preceding mood state and on whether an AD or mood stabilizing (MS) agent was added following onset of depression. Results: Patients who became depressed following a period of euthymia were more likely to respond to treatment (62.5%) than patients who became depressed following a period of mania or hypomania (27.9%). The ratio of response to switch for previously euthymic patients was particularly favorable. Conclusion: Mood state prior to onset of depression in bipolar disorder appears to be an important clinical variable that may guide both choice of treatment administered and expectation of outcome to treatment.