BDNF and schizophrenia: This quite widespread reduction in cortical BDNF mRNA in schizophrenia having an impact on many associated cortical areas is in contrast to the lack of significant change in hippocampal BDNF mRNA in schizophrenia found earlier in this same cohort,17 suggesting that diagnostic changes in BDNF within the hippocampus are either not present18,33 or not as robust as cortical reductions are.