One of the hypotheses of depression proposes a role for BDNF in the etiology of the pathology [11,12], and it has been demonstrated that depressed patients have lower BDNF levels both in serum [13] and in the prefrontal cortex (PFC) and hippocampus (Hip) [14,15,16] with respect to healthy subjects. The gene discussed is BDNF; the disease is depressive disorder.