Hallucinogen
Hallucinogen, any one of a large number of natural or synthetic psychoactive drugs that produce marked distortions of the senses and changes in perception. Hallucinogens generally alter the way time is perceived, making it appear to slow down. As the name suggests, hallucinogens may produce hallucinations , which are shape- and color-shifts in the appearance of the outside world or, in extreme cases, the replacement of external reality with imaginary beings and landscapes. Hallucinogens may also lead to bizarre and antisocial thoughts as well as to disorientation and confusion. The physiological basis of such experiences is not clear, but evidence suggests that hallucinogens work by inhibiting the availability of serotonin, an important neurotransmitter in the brain. The best-known and most potent hallucinogen is lysergic acid diethylamide (LSD). Other hallucinogens include psilocybin, which comes from certain species of mushrooms , and mescaline, which is derived from a cactus calle