SERPINI1 and major depressive disorder: MDD and BI disorder patients showed significant downregulation in the CSF levels of LINGO1 [61–73] (p < 0.05, p < 0.05), GRIA4 [217–229] (p < 0.05, p < 0.01), CNTNAP4 [886–897] (p < 0.05, p < 0.01), and SERPINI1 [287–293] (p < 0.05, p < 0.01) in comparison to the controls.