Antidepressant drugs, unlike other drugs, have indirect targets. The vast majority of drugs after the initial administration reach an initial target and thus a consequent acute effect. Antidepressant drugs, on the other hand, require continued administration for several weeks for the therapeutic effect to appear. This is due to the fact that after administration of antidepressants, they reach an initial target, such as an increase of monoamines, but also other indirect targets, for example, in-crease in BDNF, TrkB and synapses plasticity for the remission of patients symptoms to occur, thus determining long-term adaptive effects.