A method of inducing psychedelic states in an individual, by administering mescaline, a salt thereof, analogs thereof, or derivatives thereof to the individual, and inducing a psychedelic state in the individual. A method of therapy, by administering an intermediate “good effect dose” of mescaline, salt of mescaline, analogs thereof, or derivatives thereof to an individual, and inducing positive acute drug effects that are known to be associated with more positive long-term responses in psychiatric patients. A method of therapy, by administering an “ego-dissolution” dose of mescaline, a salt of mescaline, analogs thereof, or derivatives thereof to an individual, and providing the experience of ego-dissolution.