Hallucinogens are a class of drugs that cause profound distortions in a person’s perceptions of reality, otherwise known as hallucinations. While under the influence of hallucinogens, users might see images, hear sounds or feel sensations that seem to be real but aren’t.
Almost all hallucinogens contain nitrogen and are classified as alkaloids. Many hallucinogens have chemical structures similar to those of natural neurotransmitters (acetylcholine-, serotonin-, or catecholamine-like).
The most commonly used hallucinogens are:
Hallucinogens can be man-made, or they can come from plants or mushrooms or extracts from plants and mushrooms. Generally, they are divided into two types: classic hallucinogens (LSD) or dissociative drugs (PCP). Either type of hallucinogen can cause users to have rapid, intense emotional swings.
Some of the more common hallucinogens include:1
Sometimes called hoasca, aya, and yage, ayahuasca is brewed from plants containing DMT along with an Amazonian vine that prevents the normal breakdown of DMT in the digestive system. It is usually consumed like tea.
Dimethyltryptamine, also known as Dimitri, is a natural chemical found in some Amazonian plant species, but it can also be chemically synthesized. It usually comes as a white, crystalline powder that is vaporized or smoked in a pipe or bong.
D-lysergic acid diethylamide (LSD) is a manmade chemical made from ergot, a fungus that grows on certain grains. It is probably the most powerful hallucinogen available, producing hallucinations, changes in the way reality is perceived, and altered moods.
It comes as a white powder or clear liquid and has no color or smell. It can come in capsules, but most often comes on small squares of blotter paper or gelatin that users place on the tongue or swallow to take a “trip.”
The active ingredient in marijuana is delta-9 tetrahydrocannabinol or THC, which acts on cannabinoid receptors found in brain regions that influence learning, memory, appetite, coordination, and pleasure.
THC is just one of more than 400 different active substances—and 60 different cannabinoid molecules—contained in marijuana. Widely used as a recreational and medicinal substance, marijuana has been found to cause paranoia or anxiety as well as hallucinations, especially in adolescents who use the drug regularly.2 Time distortion, which is a symptom of marijuana use, is also part of hallucination.
A natural substance found as the main ingredient in the peyote cactus. The top of the spineless peyote cactus plants has disc-shaped “buttons” that contain mescaline. The buttons are dried out and then either chewed or soaked in liquid to produce an intoxicating drink. Mescaline can also be made through chemical synthesis.
PCP is a dangerous manmade substance that was originally developed as an anesthetic but was discontinued for human use in 1965 due to side-effects. It is now an illegal street drug sold as a white powder or in liquid form. It can be snorted, injected, smoked, or swallowed.
It produces hallucinations and “out-of-body” sensations. Usage, especially in large doses, can be life-threatening and lead to serious mental health problems.
A natural substance that is found in hallucinogenic mushrooms that contain psilocybin and psilocin. In large enough doses, psilocybin can produce effects very similar to the powerful hallucinogen LSD. “Shrooms” as they are sometimes called can be used either fresh or dried. They are normally eaten, mixed with food, or brewed like tea for drinking.
How Hallucinogens Work
Scientists are not sure exactly how hallucinogens and dissociative drugs produce their effects on the user. However, classic hallucinogens are thought to affect neural circuits in the brain involving the neurotransmitter serotonin, and dissociative drugs cause their effects by primarily disrupting the actions of the brain’s glutamate system.
The regions of the brain that are affected by hallucinogens control mood, sensory perception, sleep, hunger, body temperature, sexual behavior, and muscle control, the NIDA says.3