BDNF and depressive disorder: One of the main actors responsible for modulating neuroplasticity in adults is the Brain-Derived Neurotrophic Factor (BDNF) [4], and it has been seen that in preclinical models associated with depression [5,6,7] such as chronic stress [8,9,10] there is a decrease in the central and serum concentration of BDNF, down-regulating neural plasticity, promoting neuronal atrophy, and decreasing synaptic function, expressed in its number of apical dendrites and its total dendritic spines, structures intimately involved with cognitive processes [11].