Correlation of Clinical Response With Homocysteine Reduction During Therapy With Reduced B Vitamins in Patients With MDD Who Are Positive for MTHFR C677T or A1298C Polymorphism: A Randomized, Double-Blind, Placebo-Controlled Study

Objective: This study was designed to evaluate the efficacy and safety of reduced B vitamins as monotherapy in adults with major depressive disorder (MDD) who were also positive for at least 1 methylenetetrahydrofolate reductase (MTHFR) polymorphism associated with depression and further test the hypothesis that reduced (metabolized) B vitamins will lower homocysteine in a majority of clinically responding patients. Methods: 330 adult patients with MDD (DSM-5) and positive for either MTHFR C677T or A1298C polymorphism were enrolled in a trial conducted between August 1, 2014, and April 3, 2015. 160 patients received placebo, while 170 received a capsule containing a combination of reduced B vitamins. Plasma homocysteine levels were measured at baseline and week 8. The Montgomery-Asberg Depression Rating Scale (MADRS) was used to evaluate efficacy for MDD. Results: 159 of 170 vitamin-treated patients and 123 of 160 placebo-treated patients were completers. Of the active treatment group, 131 (82.4%) showed a reduction in homocysteine (for a mean in this subgroup of 25%, P < .001), while 28 (17.6%) showed no significant change. Placebo patients demonstrated a small elevation in homocysteine. Active-treatment patients demonstrated, on average, a 12-point reduction on the MADRS by week 8, and 42% achieved full remission (P < .001). No side effect was significantly different between groups. No patients experienced mania. Conclusions: A combination of reduced B vitamins and micronutrients, when used in the treatment of MDD in patients with MTHFR polymorphism, resulted in a separation from placebo by week 2, and 42% of the treatment arm achieved remission by week 8. Further, clinical improvement correlated with a significant reduction in homocysteine levels in a majority of responders. These results support the homocysteine theory of depression and the safety and therapeutic benefit of reduced B vitamins as monotherapy for MDD, particularly in patients with MTHFR polymorphism. Trial registration: ClinicalTrials.gov identifier: NCT02709668