I would assume everyone besides those with abnormal reaction to LSD physically or psychologically wouldn't be at any risk of dying unless shitty decision making is involved outside of a psychotic state (psychotic state falls under abnormal psychological reaction, as it isn't extremely common). Intelligence really doesn't have much to do with ones ability to experience LSD and get something out of it. Psychedelic drugs manifest altered states out of ones own physiology, and the insights can be positive or negative for anyone depending on whether one takes them with a grain of salt and uses them appropriately.