A reduction in mRNA and protein expression of the glutamic acid decarboxylase-67 (GAD67), the enzyme synthesizing GABA neurotransmitter, is observed in the dorsolateral PFC of patients with schizophrenia (23–27) and is associated with a decrease in GABAergic parvalbumin (PV) interneurons. This evidence concerns the gene GAD1 and schizophrenia.