I had a one day ketamine infusion in LA with Dr. Leverone. it last 4-5 hours and i was in remission for 2 months, and off all meds. because i was on ketamine for 2 years i had a tolerance, and never reached the ideal state during the infusion, which may or may not be why it only lasted 2 months. but i am in the process of scheduling another for the end of the month. and i didn't have to have a psych eval for this. i only had to have one before i had my SCS implanted 4 years ago... which was then removed a year and a half after being implanted.