Nevertheless, given the important role of MTHFR in the metabolism on folic acid, methionine, and homocysteine, it is possible that MTHFR gene variation not only affects schizophrenia susceptibility but may also modify symptom severity [Herran et al., 1999; Goff et al., 2004] and the efficacy of folic acid supplementation and antipsychotic treatments [Joober et al., 2000; Hill et al., 2011; Vehof et al., 2012]. The gene discussed is MTHFR; the disease is schizophrenia.