Hypnosis.

Clinical hypnosis is an important therapeutic tool with an increasingly understood cognitive and neurobiological basis, and evidence for efficacy. Hypnosis involves controlled modulation of components of cognition-such as awareness, volition, perception and belief-by an external agent (the hypnotist) or by oneself (self-hypnosis) employing suggestion. In this article, we describe what hypnosis is, how it can be used in clinical settings, and how it is done.