Recurrence in Bipolar I Disorder: A Post Hoc Analysis Excluding Relapses in Two Double-blind Maintenance Studies

Objective To assess the efficacy of lamotrigine or lithium in preventing mood recurrence (i.e., a new mood episode) in bipolar disorder. Methods Data from bipolar I patients with relapses (i.e., mood episodes having the same polarity as the index episode within 90 or 180 days of randomization) were excluded from post hoc efficacy analyses of two 18-month, placebo-controlled maintenance trials of lamotrigine and lithium. Results Both lamotrigine and lithium were more effective than placebo in delaying the time to intervention for any mood episode (depression, mania, hypomania, or mixed) when relapses that occurred in the first 90 days were excluded from the analyses (p = .002, lamotrigine vs. placebo; p = .010, lithium vs. placebo). Results were similar when patients with mood episodes within 180 days of randomization were excluded. Conclusions Both lamotrigine and lithium maintenance therapy protected against mood episode recurrence in bipolar I disorder.