GRIN1 and schizophrenia: Alteration of NMDAR subunit GluN1 mRNA has been often reported to decrease by 15–30% in the post-mortem brains with schizophrenia patients83–89, while some reports showed no change90 or an increase.91 Although the findings are conflicting, one may speculate that GluN1 expression may be down-regulated in the cortex and hippocampus of patients with schizophrenia (see review by 92,93), which could lend support for NMDAR hypofunction in the cortical and hippocampal pyramidal neurons.