Lysergic acid diethylamide (LSD), also known as acid, is a psychedelic drug known for its psychological effects, which may include altered awareness of one’s surroundings, perceptions, and feelings as well as sensations and images that seem real though they are not. It is used mainly as a recreational drug and for spiritual reasons. LSD is typically either swallowed or held under the tongue. It is often sold on blotter paper, a sugar cube, or gelatin. It can also be injected, insufflated, inserted vaginally or inserted anally.
LSD is not usually addictive. However, adverse psychiatric reactions such as anxiety, paranoia, and delusions are possible. LSD is in the ergoline family. LSD is sensitive to oxygen, ultraviolet light, and chlorine, though it may last for years if it is stored away from light and moisture at low temperature. In pure form it is odorless, crystalline, and clear or white in color. As little as 20–30 micrograms can produce an effect.
LSD was first made by Albert Hofmann in Switzerland in 1938 from ergotamine, a chemical from the fungus ergot. The laboratory name for the compound was the acronym for the German Lyserg-säure-diäthylamid, followed by a sequential number: LSD-25. Hofmann discovered its psychedelic properties in 1943. LSD was introduced as a commercial medication under the trade-name Delysid for various psychiatric uses in 1947. In the 1950s, officials at the United States Central Intelligence Agency (CIA) thought the drug might be useful for mind control and chemical warfare and tested the drug on young servicemen and students, and others without their knowledge. The subsequent recreational use by youth culture in the Western world as part of 1960s counterculture resulted in its prohibition.