Efficacy of vitamins B1 and B6 as an adjunctive therapy to lithium in bipolar-I disorder: A double-blind, randomized, placebo-controlled, clinical trial

The use of adjunctive therapy for bipolar disorder is increasingly considered to increase the efficacy of standard treatments. In this randomized clinical trial, we evaluated the effect of vitamins B1 and B6 in separate treatment arms on mood symptoms, cognitive status, and sleep quality in hospitalized patients with bipolar disorder in manic episodes. In addition to receiving standard lithium treatment, participants (N = 66) were randomized to one of three conditions: 100 mg of vitamin B1, 40 mg of vitamin B6, or placebo. Outcomes were assessed one and 8 weeks of daily treatment, including the Young Mania Rating Scale (YMRS), Pittsburgh Sleep Quality Scale (PSQI), and Mini-Mental State Examination (MMSE). This study was performed between December 2020 and September 2021 based on the registration code number IRCT20200307046712N1. Vitamin B6 had a significant effect (P value < 0.025 as significant) on mood improvement compared to placebo (F (1, 27.42) = 30.25, P < 0.001, r = 0.72), but vitamin B1 had no significant effect on mood improvement compared to Placebo (F (1/35.68) = 4.76, P = 0.036, r = 0.34). The contrasts between groups on PSQI showed a significant effect (P value < 0.025 as significant) of vitamin B6 over placebo for sleep status improvement (F (1/32.91) = 16.24, P < 0.001, r = 0.57) and also a significant effect of vitamin B1 over placebo (F (1/41.21) = 13.32, P < 0.001, r = 0.49). The use of vitamin B6 as an adjunctive therapy to lithium can be associated with the improvement of mood symptoms in patients with bipolar disorder in the midst of a manic episode.