Lysergic acid diethylamide, abbreviated LSD or LSD-25, also known as lysergide and colloquially as acid, is a semisynthetic psychedelic drug of the ergoline family, well known for its psychological effects which can include altered thinking processes, closed and open eye visuals, synesthesia, an altered sense of time and spiritual experiences, as well as for its key role in 1960s counterculture. It is used mainly as an entheogen, recreational drug, and as an agent in psychedelic therapy. LSD is non-addictive, is not known to cause brain damage, and has extremely low toxicity relative to dose, although in rare cases adverse psychiatric reactions such as anxiety or delusions are possible. History
LSD was first synthesized on November 16, 1938 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. LSD's psychedelic properties were discovered 5 years later when Hofmann himself accidentally ingested an unknown quantity of the chemical.The first intentional ingestion of LSD occurred on April 19, 1943, when Hofmann ingested 250 µg of LSD. He said, this would be a threshold dose based on the dosages of other ergot alkaloids. Hofmann found the effects to be much stronger than he anticipated. Sandoz Laboratories introduced LSD as a psychiatric drug in 1947.
Albert Hofmann in 2006
LSD's effects normally last from 6–12 hours depending on dosage, tolerance, body weight and age. The Sandoz prospectus for "Delysid" warned: "intermittent disturbances of affect may occasionally persist for several days." Contrary to early reports and common belief, LSD effects do not last longer than the amount of time significant levels of the drug are present in the blood. Aghajanian and Bing (1964) found LSD had an elimination half-life of only 175 minutes. However, using more accurate techniques, Papac and Foltz (1990) reported that 1 µg/kg oral LSD given to a single male volunteer had an apparent plasma half-life of 5.1 hours, with a peak plasma concentration of 5 ng/mL at 3 hours post-dose. Dosage
A single dose of LSD may be between 100 and 500 micrograms—an amount roughly equal to one-tenth the mass of a grain of sand. Threshold effects can be felt with as little as 25 micrograms of LSD. Dosages of LSD are measured in micrograms (µg), or millionths of a gram. By comparison, dosages of most drugs, both recreational and medicinal, are measured in milligrams (mg), or thousandths of a gram. For example, an active dose of mescaline, roughly 0.2 to 0.5g, has effects comparable to 100 µg or less of LSD.[4
Neurological, Psychological and Sensory Effects
LSD can cause pupil dilation, reduced appetite (for some, it increases), and wakefulness. Other physical reactions to LSD are highly variable and nonspecific, and some of these reactions may be secondary to the psychological effects of LSD. The following symptoms have been reported: numbness, weakness, nausea, hypothermia or hyperthermia, elevated blood sugar, goose bumps and an increase in heart rate, perspiration, saliva production, mucus production, sleeplessness, hyperreflexia, and tremors. Some users, including Albert Hofmann, report a strong metallic taste for the duration of the effects. LSD is not considered addictive by the medical community. Rapid tolerance build-up prevents regular use, and there is cross-tolerance shown between LSD, mescaline and psilocybin. This tolerance diminishes after a few days without use and is probably caused by downregulation of 5-HT2A receptors in the brain
LSD's psychological effects (colloquially called a "trip") vary greatly from person to person, depending on factors such as previous experiences, state of mind and environment, as well as dose strength. They also vary from one trip to another, and even as time passes...