Although there is no evidence that supplements are helpful in the treatment of psychosis in general, based on the published studies, we believe that if we can detect MTHFR polymorphism in individuals with various psychiatric diseases, we might be able to differentiate those MTHFR-related psychiatric patients from non MTHFR deficient patients and develop specific clinical treatment strategies, such as folate or methylfolate supplement to reverse the symptoms. The gene discussed is MTHFR; the disease is psychotic disorder.