BDNF and major depressive disorder: As displayed in Table 2A, 2B and Figure 2A, 2B, upon removing cases with CP, probable MDD and GAD from the analyses, plasma BDNF showed good (AUC=0.84, 95% CI=0.74 to 0.95, p<0.001) and excellent discriminative accuracy (AUC=0.92, 95% CI=0.84 to 1.00, p<0.001) for all-cause MCI and non-amnestic MCI, respectively.