LSD

Psychedelic drug, a hallucinogen. Colourless, odourless, and easily synthesized, it is nonaddictive and nontoxic, but its effects are unpredictable. Its use is illegal in most countries.

The initials are from the German Lysergsäurediäthylamid; the drug was first synthesized by Swiss chemist Albert Hofmann (1906–2008) in 1943. In 1947 the US Central Intelligence Agency began experiments with LSD, often on unsuspecting victims. Many psychiatrists in North America used it in treatment in the 1950s. Its use as a means to increased awareness and enhanced perception was popularized in the 1960s by US psychologist Timothy Leary, novelist Ken Kesey, and chemist Augustus Owsley Stanley III (1935– ). A series of laws to ban LSD were passed in the USA from 1965 (by which time 4 million Americans were estimated to have taken it) and in the UK in 1966; other countries followed suit. The drug had great influence on the hippie movement.