Folate supplementation as a beneficial add-on treatment in relieving depressive symptoms: A meta-analysis of meta-analyses

The results of meta-analyses investigating the role of folate on depression are conflicting. The aim of this umbrella meta-analysis was to obtain an overall effect and give a concise and resolving conclusion. International scientific databases including PubMed, Scopus, and Web of Science were searched up to Oct 2023. All observational and interventional meta-analyses investigating the role of folate in depression were included in the study. Random-effects model was employed to obtain pooled results. I 2 statistics and Cochrane Q test were used to assess the between-study heterogeneity. The quality of included meta-analyses was evaluated using the Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR2) questionnaire. Overall 11 studies were included, of which 8 studies went under quantitative evaluation. The results indicated that folate supplementation significantly relieved depression symptoms [(SMD: -0.42; 95% CI: -0.57, -0.27, p < .001; I 2 = 0.0%, p-heterogeneity = 0.554) (WMD: -3.20; 95% CI: -4.00, -2.41, p < .001, I 2 = 14.8%, p-heterogeneity = 0.318)] with low levels of heterogeneity. Also, based on observational studies, folate insufficiency significantly increased the odds ratio of depression by 35% (OR:1.35; 95% CI: 1.27, 1.42, p < .001, I 2 = 8.7%, p-heterogeneity = 0.350). The findings support the fact that folate supplementation could be suggested as an efficacious and adjuvant agent in the alleviation of depression symptoms along with routine medications.

Folate as adjunct therapy to SSRI/SNRI for major depressive disorder: Systematic review & meta-analysis

OBJECTIVE

Evaluate depression scores, response, and remission rates in patients with major depression receiving adjunct therapy with folate (L-Methylfolate or folic acid) compared to selective serotonin reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor (SSRI or SNRI) monotherapy.

METHODS

Academic Search Premier, CINAHL Complete, Cochrane Database of Systematic Reviews, Medline with Full Text, PsychInfo, PubMed, ClinicalTrials.org, and Google Scholar were searched utilizing specific key words. Identified studies were independently screened for inclusion by two reviewers, were assessed for risk of bias using the Revised Cochrane risk-of-bias tool (RoB2), then meta-analyzed using a random effects model with Review Manager (5.4) software.

RESULTS

The initial search revealed 293 articles with 6 randomized control trials ultimately meeting inclusion criteria. In patients with depression, analysis of 5 studies revealed a significantly lower Hamilton Depression Rating Scale (HAM-D) score in individuals treated with adjunct therapy with l-Methylfolate/folic acid [Mean Difference (MD): -2.16 (95 % CI -3.62 to -0.69), p = 0.004], as well a combined HAM-D and Beck Depression Inventory-II (BDI-II) scores [standardized mean difference (SMD): -0.61 (95 % Confidence Interval {CI} -0.97 to -0.24), p = 0.002]. This adjunct therapy also yielded an improved response rate [Risk Ratio (RR): 1.36 (95 % CI: 1.16-1.59) P = 0.0001], increase in remission rate [RR: 1.39 (95 % CI: 1.00-1.92) P = 0.05], and reduction in depression scores after varying durations of treatment, 4 week: [SMD = -0.38 (95 % CI: -0.55 to -0.22) P ≤ 0.00001]; 6 week: [SMD = -0.94 (95 % CI: -1.85 to -0.03) P = 0.04]; ≥ 8 week: [SMD= -0.57 (95 % CI: -0.91 to -0.23) P = 0.0009].

CONCLUSION

Adjunct therapy with l-Methylfolate or folic acid improves depression scale scores, patient response, and remission rates.