Traditional antidepressants mostly act on serotonin, norepinephrine, and dopamine. Esketamine works on a different system in the brain involving glutamate and NMDA receptors, which play a role in how nerve cells form new connections. By acting on this pathway, Spravato can lift depression symptoms for some people when the usual medications have not, and it can begin to help more quickly than many oral antidepressants.