In the New England Journal of Medicine this week, lead author Dr. Lakshmi Yatham and a team of researchers have published the results from the world’s first randomized clinical trial assessing the duration of adjunctive antidepressant therapy in bipolar depression, the findings of which show that, while the primary outcome of time to any mood episode was not significant, pre-specified sensitivity analysis and secondary outcomes suggest extending the treatment period beyond current guidelines may help prevent depressive relapses.
The clinical trial, conducted at sites in Canada, South Korea and India, involved 178 patients with Bipolar I disorder who were in remission from a depressive episode following treatment with modern antidepressant drugs (escitalopram or bupropion XL). The patients were randomly assigned to either continue antidepressant treatment for 52 weeks, or begin tapering off antidepressants at six weeks and switch to a placebo at eight weeks.
Over the year-long study, 46 per cent of patients in the placebo group experienced a relapse of a mood event, compared to only 31 per cent in the group that continued antidepressant treatment. While this primary outcome was not found to be statistically significant, the comparison included relapses that occurred during the first six weeks of the study when both groups were receiving the same treatment.
However, in an analysis from week six onward, when treatment between the two groups differed, patients that continued antidepressant treatment were 40 per cent less likely to experience a relapse of any mood event, and 59 per cent less likely to experience a depressive episode relative to the placebo group.