Other studies also revealed altered levels of glutamate, N-acetylaspartylglutamate, kynurenic acid, and the activity of glutamate carboxypeptidase II in schizophrenia [79,80,81,82] (N-acetylaspartyl-glutamate, which is degraded by glutamate carboxypeptidase II, is an endogenous NMDAR antagonist and mGlu3R agonist [83,84]). Here, FOLH1 is linked to schizophrenia.