BDNF and schizophrenia: For instance, in a number of patients with schizophrenia, a decrease in BDNF protein and mRNA has been detected in the hippocampus, prefrontal cortex, anterior cingulate cortex, and superior temporal gyrus (Hashimoto et al., 2005; Issa et al., 2010; Ray et al., 2011, 2014; Ray et al., 2014; Thompson et al., 2014), as well as the reduction of NTRK2 and NTRK3 (neurotrophin receptors) mRNA in the dorsolateral prefrontal cortex (Weickert et al., 2005).