Comparison of the efficacy and safety of quetiapine and lithium for bipolar depression: A systematic review and meta-analysis of randomized controlled trials

Aim: Pharmacological treatments recommended for bipolar depression are inconsistent across guidelines. We compared the efficacy and safety of antipsychotics and mood stabilizers for bipolar depression. Methods: A systemic review and meta-analysis of randomized controlled trials comparing antipsychotics and mood stabilizers for bipolar depression was conducted based on a literature search of major electronic databases. Results: Three studies comparing quetiapine with lithium were identified and analyzed; no other antipsychotic-mood stabilizer combinations were found. The meta-analysis revealed no significant differences between quetiapine and lithium for the following outcomes: (1) remission from depressive episodes (risk ratio [RR]: 1.80, 95% CI: 0.51-6.40, P = 0.36), (2) changes in depressive symptom (standardized mean difference: -0.22, 95% CI: -0.52-0.08, P = 0.15), (3) changes in social function (standardized mean difference: -0.00, 95% CI: -0.19-0.18, P = 0.98), (4) suicide-related events (odds ratio [OR]: 2.35, 95% CI: 0.40-13.65, P = 0.34), (5) severe adverse events (OR: 1.63, 95% CI: 0.51-5.20, P = 0.41), (6) dropouts due to adverse events (RR: 1.19, 95% CI: 0.76-1.87, P = 0.45, 7) dropout for any reasons (RR: 0.95, 95% CI: 0.74-1.22, P = 0.70). Conclusion: Although this study found no differences in the efficacy and safety of quetiapine and lithium for bipolar depression, a comprehensive comparison of antipsychotics and mood stabilizers was not performed. Further studies are needed to clarify which of these, not just quetiapine and lithium, is more useful for bipolar depression.