However, the prevalence of these polymorphisms appears to be 36–82% higher in people with severe mental illness, with meta-analyses of population data showing MTHFR polymorphisms associated with major depression (odds ratio (OR) 1.36), schizophrenia (OR 1.44) and bipolar disorder (OR 1.82) [68]. The gene discussed is MTHFR; the disease is schizophrenia.