Major depressive disorder affects an estimate of 5% of the population with nearly 1‑third of patients failing to achieve remission with conventional pharmacological treatment. Esketamine, a novel rapid‑acting antidepressant, with a noncompetitive antagonism on N‑methyl‑D‑Aspartate receptor, have been recently approved by Food and Drug Administration (FDA) and European Medicines Agency (EMA) for...