Advertisement poster of 1857: "Instant sleep. Miscellaneous effects of paralysis, partial and complete catalepsy, partial or complete attraction. Phreno-magnetic effects... Musical ecstasy... Insensitivity to physical pain and instant awakening... transfusion of magnetic power to others..."
Usually, one person (the "hypnotist") talks to another (the "subject") in a special way that puts the subject into a trance. While the subject is in this state, he can be influenced by suggestions. The hypnotist can tell him to forget his name, or that the room is hot (he will start sweating), or that he is someone else. Hypnotic suggestions may be delivered by a hypnotist in the presence of the subject, or may be self-administered ('self-suggestion' or 'autosuggestion'). The use of hypnotism for therapeutic purposes is referred to as 'hypnotherapy', while its use as a form of entertainment for an audience is known as 'stage hypnosis'.
Contrary to a popular misconception—that hypnosis is a form of unconsciousness resembling sleep—some contemporary research suggests that hypnotic subjects are fully awake and are focusing attention, with a corresponding decrease in their peripheral awareness. Subjects also show an increased response to suggestions. However, the behaviour of subjects under hypnotism goes so far beyond normal focused attention that the description of "altered state of consciousness" is more used.
Hypnotherapy is when a hypnotist uses hypnosis to help the subject heal emotionally, or to heal a sick mind. Hypnotherapy is hypnosis used for therapy.
Hypnosis can also be done by one person acting alone. Then he is acting as both hypnotist and subject. This is called "self-hypnosis," or sometimes "auto-suggestion." In some cases, this is simply a form of using trance.