GAD1 and schizophrenia: In patients with schizophrenia, the expression of glutamic acid decarboxylase 67 (GAD67), which is mostly responsible for GABA synthesis, and GABA transporter-1 (GAT-1), which is primarily responsible for GABA reuptake, in a subset of GABAergic neurons decreased compared to controls, which may indicate an alteration of the inhibitory tone on pyramidal cells (De Jonge et al., 2017).