Lysergic acid diethylamide, commonly known as LSD (from German Lysergsäure-diethylamid), is a potent psychedelic drug that intensifies thoughts, emotions, and sensory perception.

[31][32] Stanislav Grof has written that religious and mystical experiences observed during LSD sessions appear to be phenomenologically indistinguishable from similar descriptions in the sacred scriptures of the great religions of the world and the texts of ancient civilizations.

Commonly observed symptoms include increased body temperature, blood sugar, and heart rate, as well as goose bumps, jaw clenching, dry mouth, and hyperreflexia.

[48][49] LSD induces an animated sensory experience affecting senses, emotions, memories, time, and awareness, lasting from 6 to 20 hours, with the duration dependent on dosage and individual tolerance.

[50][51] Users may experience enhanced visual phenomena, such as vibrant colors, objects appearing to morph, ripple or move, and geometric patterns on various surfaces.

Despite lower rates of depression and substance abuse found in psychedelic drug users compared to controls, LSD presents heightened risks for individuals with severe mental illnesses like schizophrenia.

[61][62][63][non-primary source needed] Flashbacks are psychological episodes where individuals re-experience some of LSD's subjective effects after the drug has worn off, persisting for days or months post-hallucinogen use.

[7][69]: 145  Interactions between psychedelics and antipsychotics or anticonvulsants are not well-documented; however, co-use with mood stabilizers like lithium may induce seizures and dissociative effects, particularly in individuals with bipolar disorder.

[7][93] Individuals experiencing a bad trip after LSD intoxication may present with severe anxiety and tachycardia, often accompanied by phases of psychotic agitation and varying degrees of delusions.

[57] Cases of death on a bad trip have been reported due to prone maximal restraint (commonly known as a hogtie) and positional asphyxia when the individuals were restrained by law enforcement personnel.

[103][104][105] Despite its high potency, recreational doses of LSD have only produced low incidents of acute toxicity, but NBOMe compounds have extremely different safety profiles.

Retrosynthetically, the C-5 stereocenter could be analysed as having the same configuration of the alpha carbon of the naturally occurring amino acid L-tryptophan, the precursor to all biosynthetic ergoline compounds.

[151][153] "LSD," writes the chemist Alexander Shulgin, "is an unusually fragile molecule ... As a salt, in water, cold, and free from air and light exposure, it is stable indefinitely.

[156] LSD may be quantified in urine for drug testing programs, in plasma or serum to confirm poisoning in hospitalized victims, or in whole blood for forensic investigations.

In a dreamlike state, with eyes closed (I found the daylight to be unpleasantly glaring), I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors.

Swiss chemist Albert Hofmann first synthesized LSD in 1938 from lysergic acid, a chemical derived from the hydrolysis of ergotamine, an alkaloid found in ergot, a fungus that infects grain.

This resulted in LSD being viewed as a cultural threat to American values and the Vietnam War effort, and it was designated as a Schedule I (illegal for medical as well as recreational use) substance in 1968.

[171] LSD was first synthesized on November 16, 1938[172] by Swiss chemist Albert Hofmann at the Sandoz Laboratories in Basel, Switzerland as part of a large research program searching for medically useful ergot alkaloid derivatives.

[178] Experiments included administering LSD to CIA employees, military personnel, doctors, other government agents, prostitutes, mentally ill patients, and members of the general public to study their reactions, usually without the subjects' knowledge.

[180] In the early 1960s the use of LSD and other hallucinogens was advocated by new proponents of consciousness expansion such as Leary, Huxley, Alan Watts and Arthur Koestler,[181][182] and according to L. R. Veysey they profoundly influenced the thinking of the new generation of youth.

[187] Around this time, the Merry Pranksters, associated with novelist Ken Kesey, organized the Acid Tests, events in San Francisco involving LSD consumption, accompanied by light shows and improvised music.

[188][189] Their activities, including cross-country trips in a psychedelically decorated bus and interactions with major figures of the beat movement, were later documented in Tom Wolfe's The Electric Kool-Aid Acid Test (1968).

[190] In San Francisco's Haight-Ashbury neighborhood, the Psychedelic Shop was opened in January 1966 by brothers Ron and Jay Thelin to promote the safe use of LSD.

[193] The influence of LSD in the realms of music and art became pronounced in the 1960s, especially through the Acid Tests and related events involving bands like the Grateful Dead, Jefferson Airplane, and Big Brother and the Holding Company.

[194] In the United Kingdom, Michael Hollingshead, reputed for introducing LSD to various artists and musicians like Storm Thorgerson, Donovan, Keith Richards, and members of the Beatles, played a significant role in the drug's proliferation in the British art and music scene.

[195] Psychedelic music of the 1960s often sought to replicate the LSD experience, incorporating exotic instrumentation, electric guitars with effects pedals, and elaborate studio techniques.

[198][page needed][199] Contemporary artists influenced by LSD include Keith Haring in the visual arts,[200] various electronic dance music creators,[201] and the jam band Phish.

Tim Scully, a prominent chemist, made some of these tablets, but said that most "Sunshine" in the USA came by way of Ronald Stark, who imported approximately thirty-five million doses from Europe.

Some psychiatrists, such as Ronald A. Sandison, who pioneered its use at Powick Hospital in England, believed LSD was especially useful at helping patients to "unblock" repressed subconscious material through other psychotherapeutic methods,[245] and also for treating alcoholism.

[246][247] One study concluded, "The root of the therapeutic value of the LSD experience is its potential for producing self-acceptance and self-surrender,"[25] presumably by forcing the user to face issues and problems in that individual's psyche.