In a different approach, a recent meta-analysis examining the association between MTHFR gene polymorphisms and psychiatric disorders demonstrated a strong association between the MTHFR C677T gene variant and unipolar depression, schizophrenia and bipolar disorder, with odds ratios of 1.36, 1.44 and 1.82, respectively [20]. Here, MTHFR is linked to schizophrenia.