LINGO1 and major depressive disorder: 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).