DPP6 and schizophrenia: We analyzed the CSF from participants with schizophrenia and healthy controls and evaluated anti-neuronal antibodies, including NMDAR, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), leucine-rich glioma-inactivated 1 (LGI1), dipeptidyl aminopeptidase-like protein 6 (DPPX), contactin-associated protein-like 2 (Caspr2), and γ-aminobutyric acid B receptor (GABABR) via cell-based assay (CBA) and other autoantibodies via tissue-based assay (TBA) using rodent brain.