A tranquilizer refers to a drug which is designed for the treatment of anxiety, fear, tension, agitation, and disturbances of the mind, specifically to reduce states of anxiety and tension. Tranquilizer, as a term, was first used by F.F. Yonkman (1953), from the conclusions of investigative studies using the drug Reserpine, showed the drug had a calming effect on all animals it was administered to. Reserpine, is a Centrally Acting Rauwolfia Alkaloid. The word directly refers to the state of tranquility in a person and other animals. The term is considered popular or common, meaning it's not generally in use in the field of medicine. Specifically, it's not used in reference to anti-psychotic or neuroleptics medications. The term is generally used as a synonym for sedative. When used by health care professionals, it is usually qualified or replaced with more precise terms: Mood stabilizers might also be considered to belong to the classification of tranquilizing agents.