It can be habit forming and people can experience symptoms similar to opiate withdrawal when stopping after extended use. For me I became quite depressed and experienced "flow of tears" when I stopped. Hands down this was the best thing I ever tried for my pain, however. I could go on and on. It really frustrated me when this was (and still marketed as) a "legal high" because whenever something natural is presented in that way it loses legitimacy as a viable medical treatment.