CO can be produced by oxidative catabolism through injection of heme oxygenase (HO).[10] CO has a similar affinity to NO-bound sGC, but CO-sGC is 25 to 50 times less active than NO-sGC.[11] This paper describes research on gas therapy for depression and schizophrenia using the endogenous gas production strategies of NO and CO as examples. This evidence concerns the gene SGCB and major depressive disorder.