Potential role of amino acids in pathogenesis of schizophrenia.

Schizophrenia is a syndrome of inconclusive etiopathogenesis with a prevalence of about 1% in general population. Underlying factors include genetic predisposition and defected neurodevelopment in early stages of life. The role of amino acids has been indicated in some reports. However, very few workers have detailed the effect of each amino acid in the pathophysiology of schizophrenia. Thus, in the present review, we aimed to provide an insight into the potential role of amino acids levels during schizophrenia. Any single amino acid defect cannot lead to the development of the disease. Higher concentration of glycine, serine, glutamate, homocysteine, and arginine are reported by many scientists in blood samples of patients of schizophrenia. Levels of rest of the amino acids show inconsistent results. Involvement of glutamate in pathophysiology of schizophrenia was hypothesized as early as the 1980s. It was demonstrated that dissociative anesthetics which are N-methyl-D-aspartate (NMDA) receptor antagonists can produce all negative, psychotic, cognitive, and physiological features of schizophrenia in healthy controls. This led to the development of hypothesis of NMDA receptor hypofunctioning in the pathophysiology of schizophrenia. Later on, it was also found that agents enhancing functioning of NMDA receptor at glycine modulatory site, improved symptoms in patients of schizophrenia receiving antipsychotic medications. Thus, the relationship of perturb amino acid levels with the biological basis and pathophysiology of schizophrenia is an important area to be further explored for effective management of schizophrenic patients.