I've done lots of drugs, but really only out of curiosity and boredom. I've gone on long binges of weed and alcohol many times, and then stopped just as abruptly as I started, with no withdrawal symptoms or any hardships of any kind.
The only drugs I'm really curious about are psychedelics, I've done mild doses of LSD (<one tab) and Salvia a couple times, and mushrooms once. The LSD was amazing, every single time, it was like an intense spiritual journey, hours and hours of intense non-stop Ti thinking. Every trip was like two months of thinking packed into a few hours, and always ended with some great realizations. LSD is THE DRUG for INTPs. Highly recommended, it has virtually no dangers except the risk of a bad trip, which is easy to avoid if you do it responsibly.
As for the fear most people have of "losing control of their faculties", I myself, and I think this would be true for most INTPs, always have that rational Ti at the forefront of my mind, always keeping me in check, never letting me get out of hand (when on mushrooms, I was a little tired at the beginning, so I drank a lot of cola and took a nap, so that I would wake up from having to pee and the caffeine, then I walked around, but only in the light and listened to happy music, all this to keep me from going into a bad trip, there were a few moments where I saw really scary stuff, but I immediately forced myself to calm down, and told myself it was only the mushrooms. Basically I stayed very rational and "in control". It was the same with LSD too, except I always took it before sunrise, so never even came close to a bad trip, but I was always careful about not losing my keys, staying hydrated, stuff like that).
The only drug that has ever come close to making me lose control was alcohol.