I have not tried it personally, but it is used in our emergency department for what are called conscious sedations. I have to attend all these sessions to ensure the patient keeps breathing, even though ketamine is not known to affect respiratory drive. Basically it just dissociates the patient from the moment while they are having a shoulder reduction or an abscess drained etc..
During this period, most people act like they are on a really bad trip and can freak out/act violent. When the med wears off, they don’t recall any of that. In these instances though, it looks like a horrible drug and some of our physicians won’t even use it.
A therapeutic low dose could be interesting, but going in for a 45 minute to 2 hr infusion session seems kind of odd. Maybe the theory is that it resets the brain and/or nervous system?