Significance of NMDA receptor-related glutamatergic amino acid levels in peripheral blood of patients with schizophrenia

► Several excitatory amino acids were studied to find a biological marker for schizophrenia. ► Peripheral blood levels of endogenous glycine and alanine could be “symptomatic marker”. ► Exogenous glycine and alanine in augmentation therapies could be therapeutic markers. ► Endogenous d-serine may prove to be the useful 'diagnostic' and 'therapeutic' marker.