Lysergic acid diethylamide, or LSD, is a powerful hallucinogenic drug. When an individual uses a hallucinogenic drug, he or she experiences hallucinations—vivid sights, sounds, smells, tastes, or other sensations that are occurring only within the user's mind but seem to be real. LSD is also sometimes called a psychedelic drug because of its ability to cause hallucinations and to make the user lose touch with reality. In fact, LSD can sometimes have such profound effects on a user's ability to distinguish what is real from what is happening inside his or her own head, that it can make the user appear to be suffering from psychosis, a state of mind that robs an individual of the ability to think clearly, reason effectively, exercise good judgment, and understand reality.

LSD crystals, discovered in 1938, are clear, odorless, and often...