Lysergic acid diethylamide, better known as LSD, is a chemical that alters a user's mood, thoughts or perceptions. For this reason, LSD is grouped into a class of drugs known as hallucinogens or psychedelics. These drugs can cause auditory, visual or somatosensory hallucinations, paranoia or dream-like states.
LSD Pills
Image courtesy of the Indiana Prevention Resource Center
LSD was first synthesized from a fungus that grows on rye and other grains. In 1938, Albert Hofmann working in the Swiss pharmaceutical company called Sandoz, produced LSD for the first time. He was hoping that this new drug could be used to stimulate circulation and respiration. However, the tests he conducted were all failures and he forgot about LSD for 5 years. In 1943, Hofmann accidentally ingested (or somehow absorbed) a bit of LSD and experienced some of the psychedelic effects of this chemical: dizziness, visual distortions and restlessness. A few days later he prepared 0.25 mg of LSD in water and drank it. He again experienced the mood and thought altering effects of LSD.

Effects of LSD on the Nervous System

LSD is water soluble, odorless, colorless and tasteless - it is a very powerful drug - a dose as small as a single grain of salt (about 0.010 mg) can produce some effects. Psychedelic effects are produced at higher doses of about 0.050-0.100 mg. The effects of LSD depend on a user's mood and expectations of what the drug will do and last several hours. The behavioral effects that LSD can produce include:

  • Feelings of "strangeness"
  • Vivid colors
  • Hallucinations
  • Confusion, panic, psychosis, anxiety
  • Emotional reactions like fear, happiness or sadness
  • Distortion of the senses and of time and space
  • "Flashback" reactions - these are the effects of LSD that occur even after the user has not taken LSD for months or even years.
  • Increases in heart rate and blood pressure
  • Chills
  • Muscle weakness

Tolerance to the effects of LSD develops quickly and users must increase their intake of LSD to get the same effects. The exact neural pathways that are affected by LSD are not completely known. LSD has a chemical structure that is very similar to the neurotransmitter called serotonin. It is thought that the effects of LSD are caused by stimulation of serotonin receptors on neurons, perhaps in the brain area called the raphe nuclei. However, it is still not clear what produces all the effects of LSD.

Did you know?

The Controlled Substances Act of 1970 states that the mandatory penalty for possession of 1 gram of LSD is 5 years in prison.

Albert Hofmann, the Swiss chemist who discovered the psychoactive drug LSD in 1938, died on April 29, 2008. He was 102 years old.


For more information about LSD and other hallucinogens, see:
  1. My Problem Child - by the discoverer of LSD, Albert Hofmann
  2. LSD - Missouri Dept. of Mental Health
  3. LSD from the National Institute on Drug Abuse.
  4. LSD - National Families in Action



GO TO: Alcohol Amphetamines Caffeine Cocaine
Heroin Inhalants LSD Marijuana
Nicotine Ecstasy Rohypnol 1,4-Butanediol
GHB Barbiturates PCP Hallucinogenic Mushrooms

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