Ketamine and esketamine are the antidepressants that have the highest efficacy of any antidepressant ever, with some current data showing 63% efficacy after a single treatment for TRD (Treatment Resistant Depression.) And 83% overall success in TRD with multiple treatments.
Because of the abuse potential, Ketamine is a Schedule III Controlled Substance and the FDA’s REMS requirements require 2 hours observation after treatment, making it more expensive, but this efficacy is unheard of in antidepressants, where even the best are little more effective than placebo, and have a slow onset of action.
We have got to stop putting the needs of people that will abuse these drugs over the needs of the people who will benefit from them.
To sum it up for lay people, this is basically a hard reset on PTSD and Major Depression, working in part through brain NMDA excitatory glutamate system antagonism and in part as a σ agonist.