Drug Facts: How Hallucinogens Work

First published 2003. To view the latest Heads Up content, click here.

LSD Messes Up Messages in the Brain

Hallucinogens are drugs that dramatically alter perceptions. Some hallucinogens are produced solely by nature. These include psilocybin, found in certain mushrooms (“magic mushrooms” or “shrooms”) and mescaline, the chemical found in the peyote cactus. LSD is semi-synthetic, or artificial.

LSD strongly affects areas of the brain involved in sensory perception, mood, and cognition.

LSD (lysergic acid diethylamide) was invented by a chemist in 1938. Working in a lab in Switzerland, Albert Hofmann was trying to create medicine out of a fungus. He ended up with LSD. Five years after he created it, Hofmann accidentally ingested the drug and took the first bad trip: “A demon had invaded me,” he said. “[It] had taken possession of my body, mind, and soul.”

LSD and other hallucinogens powerfully distort the functioning of the five senses, as well as one’s sense of time and space. Some users even report a blending of the senses—seeing sounds and hearing colors—known as “synesthesia.” An LSD trip may include terrifying experiences and inspire dangerous behavior on a user’s part.

Two long-term effects reported by former users are psychosis and hallucinogen persisting perception disorder (HPPD). Psychosis is a severe mental illness, in which a person loses contact with reality. HPPD (often but less accurately called “flashbacks”) is a disorder that includes ongoing perception problems.

LSD binds to and activates a specific receptor for serotonin, a brain chemical involved in emotions and the senses. It especially affects two brain regions: the cerebral cortex—involved in mood, cognition, and perception—and the locus ceruleus, which receives sensory signals.

“The main reason LSD is dangerous is because it’s unpredictable in its effects,” says NIDA’s Dr. Jerry Frankenheim. “The most dangerous thing that can happen is that someone has a complete break with reality and thinks they can fly or stop traffic.”

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