Considering the pivotal function of BDNF, it has been suggested that the BDNF Val66Met may have a role in the etiology of several neurological diseases (Egan et al., 2003; Notaras and van den Buuse, 2018; Shen et al., 2018) and psychiatric disorders (Kishi et al., 2018). This evidence concerns the gene BDNF and psychiatric disorder.