LSD or lysergic acid diethylamidelī˝sûr´jĭk, dī˝ĕth´ələmĭd, dī˝ĕthəlăm´ĭd [key], 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.

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