Despite the difference in the percentage of patients with elevated CSF/serum albumin ratio in the studied groups, the analysis demonstrates significant downregulation of LINGO1 [61–73], GRIA4 [217–229], CNTNAP4 [886–897] and SERPINI1 [287–293] in both MDD and BI patients in comparison to controls, respectively, and NRXN3 in MDD, BI, and SCZ in comparison to the controls, respectively (Fig. 4). This evidence concerns the gene SERPINI1 and major depressive disorder.