GRIK2 and schizophrenia: In a cohort of 250 patients with chronic schizophrenia under clozapine treatment, the impact of SNPs in SLC1A1, Glutamate Ionotropic Receptor Kainate Type Subunit 2 (GRIK2), and N-methyl-D-aspartate receptor subunit 2B (GRIN2B) genes on OCS was assessed [38].