GAD1 and schizophrenia: This decrease in GABAergic function in schizophrenia may be caused by the epigenetic silencing of glutamic acid decarboxylase67 (GAD67) expression due to both increase DNA methyltransferase (DNMT) and lower levels of histone deacetylase2 (HDAC2 activity) in dorsolateral prefrontal cortex observed in postmortem brains of patients with schizophrenia, as well as some similar findings in peripheral lymphocytes (12–17).