Comparative evaluation of quetiapine plus lamotrigine combination versus quetiapine monotherapy (and folic acid versus placebo) in bipolar depression (CEQUEL): a 2 × 2 factorial randomised trial.

Study answer

What this study found

Folic acid did not improve depressive symptoms or remission compared with placebo. For depressive symptoms, there was no consistent benefit at 12 weeks (adjusted mean difference 0.75, 95% CI -1.16 to 2.66; p=0.441), 22 weeks (0.17, -1.97 to 2.30; p=0.878), or 52 weeks (-0.92, -3.20 to 1.35; p=0.423). A treatment interaction was seen at 12 weeks, and excluding those randomized to folic acid yielded a larger lamotrigine effect, suggesting folic acid may have attenuated lamotrigine response in the factorial design. Overall, the supplement did not provide a clear antidepressant benefit in…

Study & population

Randomised, double comparison 2x2 factorial trial across 27 sites in the United Kingdom.

Intervention

Folic acid was given orally at 500 microg/day versus placebo within a 2x2 factorial trial in adults with bipolar depression receiving quetiapine, with separate randomization to lamotrigine or lamotrigine placebo.

Key limitation

Interpretation is complicated by the factorial design and an observed interaction with lamotrigine at 12 weeks.

View full study detailsView sourceOpen PDF

Original abstract