Fig. 2From: Serum folate levels in bipolar disorder: a systematic review and meta-analysisForest plot of the current meta-analysis of serum folate levels in patients with bipolar disorder and controls. Figure 2 indicated the significantly lower serum folate levels in the BD patients than that of controls (Hedges’ g = − 0.211, 95% CI = -0.391 to − 0.031, p = 0.021). Abbreviation: BD: bipolar disorder; CI: confidence intervalBack to article page