BDNF and major depressive disorder: Domenici et al.11 found that brain-derived neurotrophic factor, Rantes and epidermal growth factor were most strongly related to schizophrenia, but we found no association for these markers with MDD, and neither for the five schizophrenia markers identified in the study by Hayes et al.47 For bipolar disorder, Herberth et al.7 found 22 markers for bipolar disorder, of which 1 was correspondingly related to MDD in our sample (higher MIF).