L-arginine is the precursor of nitric oxide (NO), a neuromodulator of dopamine, gamma-aminobutyrate (GABA) and glutamate systems. Nitric oxide donors which increase NO levels at the cellular level could improve N-methyl-D-aspartate (NMDA) receptor dysfunction. Using L-arginine could bypass the blocked NMDA receptors and improve the therapeutic efficacy by reversing the dysfunction.
The investigators proposed that using L-Arginine, a dietary supplement in most cultures, might constitute a safe option as an add-on treatment which may display beneficial effects on positive, negative, cognitive and affective symptoms associated with schizophrenia.