CNDP1 and major depressive disorder: To assess the gender’s effect on the levels of measured peptides in CSF, we performed a two-way ANOVA test on the MDD and controls data, we set the disease as a first variable and the gender as a second variable, and the analysis pointed out a weak gender effect on the CSF levels of CARTPT [104–113] (interaction p = 0.0393), NXPH1 [57–63] (interaction p = 0.0174), VGF [585–594] (interaction p = 0.0343), and CNDP1 [244–253] (interaction p = 0.0215), while the analysis showed no gender’s effect on the CSF levels of all other measured peptides.