Trials on veterans suggest the potent hallucinogen could provide a new treatment for PTSD, but scientists still don't know how it works. Elias Kfoury was making what he considered to be a last-ditch attempt to remedy years of deep psychological pain. Lying on his back in a clinic in Tijuana, Mexico, the former US Navy special operations medic was deep under the influence of ibogaine, a potent psychedelic taking him on an immersive journey through old memories. "I started seeing people that I