If I'm not mistaken, and, oh, I might be, and there's no room for a 3rd writeup--Timothy Leary coined the term "psychedelic" in order to differentiate compounds like LSD from true hallucinogens, actual hallucinations from LSD being very rare except in really high doses. Interestingly, studies have shown that under the influence of LSD people's ability to process visual data is heightened rather than interfered with by the drug.