There is a variety of literature out there describing its effeciveness against depression (especially depression which does not respond to other treatments). Unfortunately ketamine is still not a good option because of the other side effects.
What makes this literature so impactful is the identification of the mechanism by which Ketamine is having this antidepressive effect. Opening the door for the development of new compounds which will work this same way, but with out the other effects of ketamine.
That would be really revolutionary if that type of development could actually be achieved!
Modern medicine is beautiful sometimes, just the money involved in it is often such a disaster