Theories explaining what occurs during hypnosis fall into two groups. Altered state theories see hypnosis as an altered state of mind or trance, marked by a level of awareness different from the ordinary conscious state. In contrast, nonstate theories see hypnosis as a form of imaginative role-enactment.
During hypnosis, a person is said to have heightened focus and concentration. The person can concentrate intensely on a specific thought or memory, while blocking out sources of distraction. Hypnotised subjects are said to show an increased response to suggestions. Hypnosis is usually induced by a procedure known as a hypnotic induction involving a series of preliminary instructions and suggestion. 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". Stage hypnosis is often performed by mentalists practicing the art form of mentalism.