The process of producing a state of mind known as hypnosis. Although recognised for hundreds of years, the precise nature of this process is still poorly understood. One modern writer has defined hypnosis as ‘a temporary condition of altered attention, the most striking feature of which is greatly increased suggestibility’.

Hypnosis is induced by various methods, but the basis of all is some rhythmic stimulus accompanied by the repetition of carefully worded suggestions. The most commonly used method is to ask the patient to fix his or her eye on a given spot, or light, and then to keep repeating, in a quiet and soothing voice, that the patient's eyes are gradually becoming tired and that he or she will want to close them.

There are various levels of hypnosis, usually classified as light, medium, and deep, and it has been estimated that 10 per cent of people cannot be hypnotised; 35 per cent can be taken into light hypnosis; 35 per cent into medium hypnosis; and 20 per cent into deep hypnosis.

Hypnosis can be used as a treatment for some psychiatric patients, and in some people with psychosomatic conditions in which emotional or psychological disturbances precipitate physical disorders such as skin lesions or headaches. It may help to relieve pain in childbirth, and asthma may also respond to it. Some people may find hypnosis to be of help in overcoming addictions to smoking, alcohol or gambling. The process has associated risks, and its use in treatment should be by those trained in the technique and subject to a regulatory body which sets standards of practice.