The efficacy of vitamin B6 as an adjunctive therapy to lithium in improving the symptoms of acute mania in patients with bipolar disorder, type 1; a double‐blind, randomized, placebo‐controlled, clinical trial

OBJECTIVE: Vitamin B6 has been linked to a variety of probable roles, including anti‐inflammatory, homocysteine‐lowering, serotonin‐regulating, and dopamine‐lowering. In this study, we investigated the possible effect of vitamin B6 on bipolar disorder in manic episode with psychotic feature in a placebo‐controlled double‐blind clinical trial in a psychiatric hospital. METHODS: This study was performed on 50 patients who were equally divided into two groups (each group included 25 patients) using 80 mg of vitamin B6 daily or placebo. At the beginning and end of the study, they were evaluated for lab tests, inflammatory biomarkers and level of blood homocysteine. Also, at the baseline and in weeks 2, 4, and 8, they were evaluated based on the anthropometric measurements, score obtained from the Young Mania Questionnaire, Mini‐Mental State Examination (MMSE), and the Pittsburgh Sleep Questionnaire. RESULTS: Accordingly, based on Yang Mania scoring scale, no significant difference was observed between the two groups receiving vitamin B6 and placebo (22.68 ± 5.39 vs. 21.80 ± 5.39 [p‐value = .51]). Based on MMSE, significant improvement in cognitive status was obtained in group placebo compared to vitamin B6 group (25.24 ± 1.96 vs. 24.40 ± 3.25, respectively [p‐value = .01]). At the Pittsburg scale (total, there was no statistically significant difference between the two groups receiving vitamin B6 and placebo (1.04 ± 0.20 vs. 0.48 ± 0.50 [p‐value = .23]). Additionally, no significant difference was observed between the two groups regarding the anthropometric status. CONCLUSIONS: According to this study, the daily dose of 80 mg of vitamin B6 for 8 weeks in patients with bipolar disorder in the manic episode with psychotic feature treated daily with lithium, was not associated with a significant improvement in mood status compared to the control–placebo group. It is recommended to perform similar studies in a multi‐center manner with a larger sample size and longer duration.