They hypothesized that altered glycine and homocysteine levels may contribute to N -methyl-D-aspartate receptor dysfunction and thereby influence the pathophysiology of schizophrenia.
Plasma glycine levels were significantly lower in the patients with schizophrenia than in controls, with values in male and female patients being 15.0% and 14.3% lower than healthy men and women, respectively. A difference in the ratio of glycine to serine between patients and controls was also highly robust.
In contrast to these low glycine levels, patients with schizophrenia also had high levels of homocysteine, which were higher overall for men than for women. Indeed, homocysteine levels in male schizophrenia patients were 65% higher than in healthy males, while female patients had levels that were 25% higher than those of control women.
This was also found in first episode psychosis (unmedicated).
B12, folate and NAC may reduce elevated homocysteine.
It seems to be important to take B vitamins together with NAC, if you do take NAC.