Lysergic acid diethylamide

LSD is the shorter name for a chemical called lysergic acid diethylamide. LSD is often called by the slang name acid. LSD is a psychedelic drug that causes people who take it to witness illusions. It also alters their thought processes.

LSD was investigated as an adjunct to psychiatric therapies for disorders such as alcoholism. Currently, LSD is being investigated as a clinical tool for treating people with anxiety and depression associated with having a terminal illness. Since there is no recognized medical use for LSD, its use in medicine is experimental. The vast majority of LSD use is illegal and thus considered "drug abuse" according to some definitions.