Although it has become familiar through more than two hundred years of use as entertainment, self-help, and therapy, the hypnotic trance remains a remarkably elusive, psychological state. Most of us may think we know what hypnosis is, but few could say if asked. Although even experts do not fully agree on how to define it, the usually emphasize three related features: absorption, or selective attention, suggestibility, and dissociation. Sometimes one of these is more prominent, sometimes another. Persons in a trance tend to focus their attention narrowly; they perceive certain things clearly and vividly while excluding other stimuli from awareness and ignoring context. As a result, they often have blank faces, speak softly, and move slowly; they express their feelings and thoughts easily and my lose awareness of time and place. They sometimes have a sense of tingling, numbness or lightness. A few hypnotic subjects can produce such vivid, unusual effects as automatic writing and age regression (talking and acting like a much younger person, even a child).

One way to explain some of the more powerful hypnotic effects is to regard the trance as a dissociated state—one in which a lack of integration among knowledge, memory, and voluntary control is expressed as feelings of unreality and changes in the sense of self.

The term “hypnosis” invented in the nineteenth century, is derived from the Greek word for sleep. Hypnotized persons sometimes walk and talk as though asleep or show amnesia afterward as though awakening from a dream. Closed eyes (to screen out distractions) or suggestions of drowsiness may be used to inducing a trance. But the resemblance to sleep is superficial; electroencephalogram (EEG) studies show that hypnotized persons are fully awake and alert.

Inducing a Trance

A competent hypnotist can induce a trance in many ways; it takes a few seconds to an hour, with an average of 10 to 20 minutes. A traditional method is to relax the subject and direct attention in a confident, rhythmic, monotonous, repetitious voice to sensations that are usually ignored: “Your eyelids are getting heavy”; Your legs are numb”; You cannot separate your clasped hands.” For some subjects it is enough simply to repeat, “Relax, focus, float.” The trance may be deepened by visual imagery: “Imagine riding a long escalator downward.” Another method is to fix he eyes on a target like a coin, a swinging pocket watch, or a dot on a blank sheet of paper. There are also many indirect ways of diverting and fixing attention. It is almost never difficult to end a trance; the hypnotist simply suggests that the subject will come out of it.

Hypnosis is not mind control. Persons in a trance may feel as if their actions are involuntary; their suggestibility also makes them highly responsive to guidance and particularly include to comply with instructions and requests from the person who has helped to induce the trance and remains a focus of concentration. But hypnotists have no unique powers, and they need not be charismatic or flamboyant. People cannot ordinarily be hypnotized against their will or forced to do or say anything they find truly objectionable. They do not do anything that seriously conflicts with their usual standards of behavior. Hypnosis is not a truth serum either; persons in a trance cannot be forced to make unwanted self-revelations, and they are quite capable of lying deliberately or unconsciously. Memories brought to light through hypnotic sage regression are not necessarily more accurate or reliable than any other memories.

Anyone who is hypnotizable can be taught self-hypnosis. Most people can learn to hypnotize herself or himself. Often people become entranced spontaneously, losing themselves in daydreaming or through imaginative involvement in a task or activity. A hypnotist is really a guide who provides cues for entering a trance and for thoughts and actions during the trance. It is said that in an important sense, all hypnosis is self-hypnosis.

Hypnotic Susceptibility

Many experts, but not all, believe that each person has a more or less stable hypnotic capacity. Five to 20 percent are highly hypnotizable, and about 30 percent are hardly susceptible at all. According to some estimates, 90 percent can achieve a light trance, 70 percent a trance of medium depth, and 10 to 20 percent a deep trance. A highly hypnotizable person enters a trance quickly and easily and is more likely to show the most dramatic effects—amnesia, hallucinations, automatic writing or age regression. Various measures of hypnotic susceptibility have been proposed and used in clinical scales and profiles: ability to roll the eyeballs far upward, postural sway, or willingness to fall backward on instruction; ability to produce a feeling of rigidity or levitation in an arm; ability to conjure up a sweet taste in the mouth. But some authorities believe that hypnotizability cannot be measured on a single scale, because the trance is not a uniform state: a capacity for absorption is not the same as suggestibility or a tendency to dissociation.

Women and men are equally good hypnotic subjects. People of high intelligence are probably slightly better than average. Children and adolescents are the best subjects of all; the capacity declines gradually with age. Hypnotic susceptibility seems to require a kind of psychological unguardedness—willingness to commit one’s attention fully without worrying about peripheral threats and distractions. Although this capacity is not correlated with the results of standard personality tests, there is some evidence that emotionally disturbed people are low in hypnotic susceptibility. Schizophrenic patients cannot concentrate, paranoid persons are too suspicious, obsess ional persons too defensive to let go, sociopaths too manipulative and depressed persons too difficult to distract from their own misery.

Centuries of Use

Trances of a kind that might now be called hypnotic have been incorporated into religious and healing rituals for thousands of years. Various meditative techniques also rely on similar procedures; for example, the mantra used in yogic meditation is on way of inducing a trance. But the person probably most responsible for introducing the clinical use of hypnosis in its modern form was Franz Mesmer, a charismatic healer who traveled around Europe in the eighteenth century putting on sensational displays of his power to treat various illnesses with what he called a “magnetic pass”; the word “mesmerizing” survives as a memorial of his fame.

In the late nineteenth century, Pierre Janet discovered that hypnotic suggestion could reproduce the forms of anesthesia and paralysis that occur in hysteria or somatoform disorder. Joseph Breuer and Sigmund Freud invented what they called a cathartic treatment to eliminate the symptoms of hysterical patients by hypnotic retrieval of traumatic memories. From what he learned through this work, Freud eventually developed the revolutionary idea of the dynamic (active) unconscious.

In the early twentieth century, therapeutic use of hypnosis declined, because it had developed an aura of charlatanry and seemed incompatible with scientific medicine. But interest began to revive in the 1940s and has been growing steadily ever since. The American Society for Clinical Hypnosis, founded in 1957, has thousands of members. Another important organization is the Society for Clinical and Experimental Hypnosis. The American Medical Association has also endorsed hypnosis as a legitimate aid to therapy.

The oldest form of hypnotic therapy, most commonly used in the eighteenth and nineteenth centuries, was simply to suggest that symptoms disappear. An extension of this technique to post-hypnotic suggestion: a direction given during the trance, which the patient is meant to carry out more or less automatically at some later time in response to a pre-established cue. The results of direct suggestion are rarely lasting (although temporary relief can be important in acute illness or surgery). Today hypnosis is almost always used in subtler ways that allow patients to take control of their own lives rather than depend on an authoritarian healer. The trance is used to help establish a therapeutic alliance; therapists encourage patients to frame their their own suggestions and teach them self-hypnosis.

Range of Uses

These methods can be employed in individual psychodynamic therapy, group and family therapy, behavior therapy, and cognitive therapies. In psychodynamic therapy, hypnosis is used to control anxiety, generate emotional reactions for examination, liberate fantasies and associations, retrieve memories, and accelerate the formation and resolution of the transference—the emotional relationship between patient and therapist that recapitulates childhood experiences. In behavior therapy and cognitive therapy, hypnosis has been used to enhance relaxation, generate imagery, heighten the expectation of success, and change self-defeating thoughts. It facilitates covert reinforcement, in which the patient imagines a reward after imagining the desired action, and desensitization, in which relaxation and imagery are used to eliminate phobias.

Hypnosis is not a treatment for severe mental disorders such as schizophrenia and major depression, but it has been used for almost everything else—from phobias to sexual problems and psychosomatic illnesses, to bedwetting and nail-biting in children. One of its best established therapeutic uses is the control of pain, both acute and chronic. Pain is often blocked from awareness by a kind of spontaneous self-hypnosis. Under hypnosis, a patient can learn to make the painful area feel numb, hot, or cold instead, or concentrate on feelings in other parts of the body. Images are evoked to divert attention and manipulate the sensation: an ice cube cooling the head, a switch turning off the pain, a vision of teeth floating out of the mouth before the dentist goes to work.

In these ways hypnosis can reduce the discomfort and anxiety produced by any uncomfortable medical procedure, especially in children. According to some therapists, highly hypnotizable women go into a trance when they use controlled breathing and other techniques that shorten labor and reduce pain in natural childbirth. How hypnotic pain control works is unknown. Hypnosis apparently causes no change in the body chemicals that regulate pain sensation, and physical signs of pain persist even when a person in a trance claims not to feel it.

Hypnotic imagery has also been used to treat many other physical symptoms, including asthma and gastrointestinal disorders. Hypnosis is said to alter the secretion of stomach acid, reduce tics and other involuntary movements, and even slow bleeding in hemophiliacs. It has also been used to relieve side effects of radiation and chemotherapy and to reduce the pain, depression, and anxiety of dying patients.

Eliminating unwanted habits is another use of hypnosis. Though it is not considered effective for most drug and alcohol dependence, it is used to help tobacco smokers quit. One common method is suggesting to them that they owe their bodies respect and protection. They can also be induced to imagine vividly the rewards of quitting, and taught to perform self-hypnosis when they feel tension or overwhelming craving. A post-hypnotic suggestion that cigarettes will smell and taste bad may work for a few. It is uncertain whether hypnosis is more effective than other methods of breaking nicotine dependence.

In the treatment of sexual disorders, hypnosis permits relaxation, enhanced concentration, and the rehearsal of sexual situations through visual imagery. The patient can also examine reasons for resistance to sexual arousal and use self-hypnosis in sexual situations.

Post-traumatic Stress

The use of hypnosis in the treatment of post-traumatic stress reactions was introduced during the First World War and has remained popular ever since. People often induce a dissociated state for self-protection during a traumatic event, distancing themselves from the experience or separating perceptions from feeling. Although useful in a crisis, dissociation becomes maladaptive as a chronic condition. The incompletely assimilated experience haunts victims of post-traumatic stress in the form of anxiety, nightmares, fragmentary involuntary memories, and episodes of reliving. Hypnosis is a controlled, voluntary, relatively comfortable form of dissociation that allows some patients to relive traumatic events in imagination, fully reconstruct the story of the past, and achieve a catharsis. They may also become so familiar with dissociated states through self-hypnosis that they can interrupt or control spontaneous reliving experiences and prevent the associated anxiety.

People suffering from multiple personality disorder, a post-traumatic stress reaction that usually results from child abuse, are especially susceptible to hypnosis. Their capacity to enter spontaneous trances, evident when they switch personalities, can be used to break down the barriers between personalities. Their traumatic memories can also be retrieved through age regression.

In over twenty years of using hypnosis in my practice, 100% of my clients who have worked with me prior to surgery of many different types, including child birth, have experienced the benefits referred to in the above-mentioned study. Finally, evidence is mounting that hypnosis is a safe and effective way to comfort patients and reduce health care costs.