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Definition: LSD from Merriam-Webster's Collegiate(R) Dictionary

(1950) : a semisynthetic illicit organic compound C20H25N3O derived from ergot that induces extreme sensory distortions, altered perceptions of reality, and intense emotional states, that may also produce delusions or paranoia, and that may sometimes cause panic reactions in response to the effects experienced —called also lysergic acid diethylamide

Summary Article: LSD
From The Columbia Encyclopedia

or lysergic acid diethylamide (lī´´sûr'jĭk, dī´´ĕth'ӘlӘmĭd, dī´´ĕthӘlăm'ĭd), alkaloid synthesized from lysergic acid, which is found in the fungus ergot (Claviceps purpurea). It is a hallucinogenic drug that intensifies sense perceptions and produces hallucinations, mood changes, and changes in the sense of time. It also can cause restlessness, acute anxiety, and, occasionally, depression. Although lysergic acid itself is without hallucinogenic effects, lysergic acid diethylamide, one of the most powerful drugs known, is weight for weight 5,000 times as potent as the hallucinogenic drug mescaline and 200 times as potent as psilocybin. LSD is usually taken orally from little squares of blotter paper, gelatin “windowpanes,” or tiny tablets called microdots. The period of its effects, or “trip,” is usually 8 to 12 hours. Unexpected reappearances of the hallucinations, called “flashbacks,” can occur months after taking the drug. The drug does not appear to cause psychological or physical dependence. The danger of LSD is that its effects are unpredictable, even in experienced users.


LSD was developed in 1938 by Arthur Stoll and Albert Hofmann, Swiss chemists hoping to create a headache cure. In 1943 Hofmann accidentally ingested some of the drug and discovered its hallucinogenic effect. In the 1960s and 70s it was used by millions of young people in America; its popularity waned as its reputation for bad trips and resulting accidents and suicides became known. In 1967, the federal government classified it as a Schedule I drug, i.e., having a high abuse potential and no accepted medical use, along with heroin and marijuana. In the early 1990s it again became popular, presumably because of its low cost. It is produced in clandestine laboratories.


See publications of the Drugs & Crime Data Center and Clearinghouse, the Bureau of Justice Statistics Clearinghouse, and the National Clearinghouse for Alcohol and Drug Information.

The Columbia Encyclopedia, © Columbia University Press 2018

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