Hallucinogens: A general group of pharmacological agents that can be divided into three broad categories: psychedelics, dissociatives, and delusions. Hallucinogenic drugs have played a role in civilization for thousands of years. It started with natural hallucinogens, such as peyote cactus and wild mushrooms. Now there are artificial drugs that have the same or more intense effects. These include lysergic acid diethylamide (LSD), MDMA (ecstasy), and dextromethorphan (DMX, often found in cough syrup). Within this essay I will cover the history, production and effects of hallucinogenic drugs. Peyote, a naturally produced plant, has been used as a hallucinogen as early as 200 AD. It was originally used in religious ceremonies by native Mexicans, but quickly spread to North American tribes. In 1620 the use of peyote was banned by the Spanish Inquisition. Peyote received an even more negative opinion in the 1960s, when it began to be used by the “hippie counterculture”. Its use was again banned in the Drug Abuse Control Amendment in 1965. Drugs appear to go through cycles of legality and return to being banned from use. But how do hallucinogens actually affect the brain? This particular type of narcotic affects a person's perception of reality. People hear sounds, see visions, or sense things that aren't actually happening. It overstimulates the senses and causes distortions in perception. What causes these thinking distortions? Hallucinogens such as LSD and psilocybin (found in mushrooms) cause their effect by disrupting the neurotransmitter serotonin. The serotonin system is involved in perceptual, behavioral and regulatory systems. This explains the alteration of mood, sexual behavior and senses... middle of paper... and the toxic effects of older drugs. Treatments for migraines and schizophrenia also rely on drugs that target the neurotransmitters serotonin. When it was discovered, LSD attracted considerable research interest. However, this stopped after it was placed under the US Controlled Substances Act in 1970. It was classified as a schedule drug, meaning it had a high risk of abuse and was not accepted for medical use. There are no current, forensic human studies with LSD, although there are some with MDMA, DMT, and psilocybin. But the FDA recently approved a human study examining how LSD affects the brain's neurotransmitter systems. Harvard Medical School is also looking into a study on how hallucinogens affect cluster headaches. In my opinion, there must be a way to use an LSD derivative in psychological research or treatment and I believe researchers will find one sooner or later..