Very often in the movies or in storybooks, we see, plus read about how hypnosis can be used to control the mind of a person or get them to perform wicked deeds.
Remember this is the movies and it is story telling!!
In fact hypnosis is a naturally occurring state that we all go into every single day, a classic example being falling asleep at night the Hypnogogic State and awakening in the morning the Hypnopompic State.
Other naturally occurring trance like states are being absorbed in a movie or totally engrossed in a book where the outside world fades away and we are in state of hyper absorption.
So called automatic or flow state activities are also a form of hypnosis for example playing a musical instrument so well it is effortless or a sports person in the Zone. In fact any activity done well enough for it to become automatic whereby it does not need too much conscious processing is and can be thought of as like hypnosis.
Now a trained Clinical Hypnotherapist can learn to create this state and utilise it for the benefit of clients and patients. Here it becomes Clinical or Therapeutic Hypnosis and then one can utilise psychotherapy methods within that hypnotic state for the betterment of the client or patient.
This very good article looks into a number of these potential uses:
Douglas Clark Master of Hypnotherapy