The NO system has been implicated in the treatment,22, 46, 47, 48, 49, 50, 51, 52, 53, 54 as well as the pathobiology of depression.49, 50, 55, 56, 57 We, therefore, further investigated PSD-95, nNOS, CAPON and sGC-β1. This evidence concerns the gene NOS1 and major depressive disorder.