The efficacy of lamotrigine in bipolar disorder: A systematic review and meta‐analysis

Abstract Objective To provide up‐to‐date clinical guidance on the efficacy of lamotrigine in bipolar disorder (BD). Methods Eligible studies were identified during a systematic literature search according to PRISMA‐guidelines. We included randomized controlled trials (RCTs) and cohort studies that quantitatively assessed lamotrigine's efficacy in BD. We divided the included studies into three groups: 1. acute treatment of depression, 2. acute treatment of mania and hypomania, and 3. maintenance treatment. Analyses were stratified by control group (placebo vs active comparator) and treatment strategy (monotherapy vs add‐on treatment). Results We included 20 RCTs ( n = 1166 lamotrigine users) and 20 cohort studies ( n = 11,141 lamotrigine users). Twenty‐four of these studies were included in meta‐analyses. During depressive episodes, greater decreases in depressive symptomatology were associated with initiation of lamotrigine as add‐on treatment than with placebo (SMD −0.30 [95% CI = −0.51, −0.10], df = 3, p = 0.004). Decreases in depressive symptomatology did not differ significantly between lamotrigine and the active comparator (SMD −0.28 [95% CI = −1.06, 0.50], df = 3, p = 0.488). As a maintenance treatment, lamotrigine was associated with a significantly lower relapse/recurrence rate than placebo (risk ratio (RR) 0.84 [95% CI = 0.71, 0.99], df = 2, p = 0.037). Relapse/recurrence rates did not differ significantly between lamotrigine and lithium (RR 1.06 [95% CI = 0.89, 1.25], df = 2, p = 0.513). A qualitative assessment of high‐quality register‐based studies found that lamotrigine was associated with lower hospital admission rates than other commonly used treatment regimes. Conclusions There is substantial evidence for the efficacy of lamotrigine in BD, specifically as add‐on treatment during acute depressive episodes and as maintenance treatment for preventing relapse and recurrence.