As recently as the early 1980’s, conventional medicine tended to treat body and mind as separate entities and saw them as the concern of distinct medical specialties. However, scientific evidence is now accumulating to support the underlying theory of holistic medicine, which is that the mind and body are inextricably linked and that the health of one influences the other. This area of research and practice is known as mind/body medicine.
The possibility that something as intangible as emotion might modify the behavior of cells in the body raises the question of whether psychological factors can actually cause, prevent or even treat disease. And if so, by what means?
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Psychoneuroimmunology (PNI) is the scientific study of the interrelations between the mind (‘’Psycho”), nervous and hormone systems (‘’neuro”) and the immune system (‘’Immunology”). Interest in mind/body research was aroused in 1974, when US psychologist Robert Ader and immunologist Nicholas Cohen conditioned laboratory rats to decrease their number of disease-fighting T-cells in response to a cue of sweetened water, evidence that a connection exists between the brain and the immune system, the body’s defence against infection and disease.
When scientists from different disciplines, psychology, immunology and endocrinology (the study of hormones) began to work together, they learned more about hormones and neurotransmitters, chemical messengers from nerve endings that ‘’lock on” to cells in other body systems. They were able to track the pathways linking stress the brain and physiological processes such as breathing and digestion. The hormones adrenaline and cortisol, for example, which are produced by the body I stressful situations, were shown to suppress the immune response, the body’s defensive reaction to antigens, or foreign substances.
The answer may be provided by US research into a group of neurotransmitters known as neuropeptides, carried out by Dr. Candace Pert at Rutgers University. Neuropeptides are chemicals that act as a messenger within the nervous system. They enable different body systems such as the endocrine system, which regulates hormones, the digestive system, the reproductive system and the immune system, to send signals to one another, propelled through tissues as well as the nerves between them.
On the surfaces of cells in all these systems are receptors. Each receptor act as a ‘’lock” for a particular neuropeptide, which slips in like a key and turns on the relevant body process. For example, when laboratory rats are injected with a neuropeptide linked with thirst, they drink continuously, even when sated with fluid. Their kidneys retain urine because the message to the body is ‘’ want water, save water”.
According to Dr. Pert, emotions may be the trigger that sends a surge of neuropeptides through the body. In 1975, the discovery of a type of neuropeptide called endorphins, natural opiates in the brain that generate pleasurable responses, showed that the brain could actually produce chemicals that change physical reactions. Further research in the 1980’s discovered endorphins not only in the brain but throughout the body, even in the immune system. Dr. Pert has speculated that as emotions fluctuate, for example from anger to pleasure, neuropeptides sweep through the body systems in response, signaling physical changes such as a rise in blood pressure or relaxation of muscles.
Viruses use the same receptors as neuropeptides, so whether or not a virus can enter a cell may depend on, how much of the appropriate type of neuropeptide is around to block it. In Dr. Pert’s opinion, the challenge lies in identifying which emotions are linked to which neuropeptides so that, theoretically, it may one day be possible to evoke a specific feeling to fight a related viral infection.
Emotions such as anxiety, stress, depression, and loneliness have been shown to affect the immune system, reducing killer T-cell activity and antibody production. In US experiments between 1984 and 1991 by psychologist Janice Kiecolt- Glaser and her husband, immunologist Ronald Glaser, of Ohio State University, blood samples taken from students before and during stressful events, such as exams, showed that the fighting power of natural killer cells slumped during these periods. Other studies have linked stress with a greater susceptibility to colds, cold sores, and other viral infections. Indeed, traumatic life events, such as bereavement or divorce, have been shown to double the risk of catching a cold.
According to research in 1987 at the State University of New York at Stony Brook, US, the antibody levels of students were higher on days when they felt buoyant and positive, and lower on days when they felt depressed and negative. Even allowing for the effects of unhealthy living on the immune system, depression has been associated with suppressed immune responses (depressed people have a greater tendency to smoke, drink alcohol, take drugs and eat an inadequate diet than those who have a positive attitude, and they also sleep and exercise less).
Stressful events can also have a long-term impact. Almost ten years after the Three Mile Island nuclear power plant threatened meltdown in 1979, people living in the area showed suppressed immune responses.
Emotional support from other people may help protect against stress and disease. In further studies by Glasers, people showing evidence of suppressed immune response included separated or divorced couples and sparring newlyweds. Medical students with plenty of friends produced more antibodies in response to a hepatitis B vaccination than those who described themselves as lonely.
Epidemiological research, which studies the connection between certain disease and the population at large, bears out these findings. In 1992, a study of heart patients at Duke University in the US showed that those without a spouse or confidant were three times as likely to die within five years of diagnosis as those who were married or had a close friend. At Stanford University, California, Dr. David Spiegel found that women with late-stage breast cancer who participated in weekly support groups reported less pain and doubled their survival times.
A study at the University of California published in 1993 found that when patients with malignant melanoma had weekly support sessions that included education, stress management, coping skills and discussion, they felt better and were more positive, although their defenses showed little change. Six months later, when support groups had discontinued, two-thirds of the group showed a rise in natural killer-cell activity and enhanced the immune response. Six years later, there were fewer cases of recurrence and higher rates of survival than for other patients. More than any research to date, this indicates that psychological factors may have a role in actually treating disease. The mind seems to play a part in auto-immune diseases, including rheumatoid arthritis, multiple sclerosis, and inflammatory bowel disease. While stress and a lack of emotional support may precipitate and exacerbate these conditions, cognitive behavioral therapy, which changes ways of thinking and behaving, can relieve symptoms, including pain and joint inflammation in rheumatoid arthritis. In 1964, US psychiatrists Dr. George Solomon and Dr. Rudolf Moos found that individuals with an inherited disposition to rheumatoid arthritis, but who were optimistic and positive-thinking, did not become ill.
A 15 years study by Dr.Stephen Greer at King’s College Hospital, London suggest that women who respond to early-stage breast cancer either with a fighting spirit or with the kind of denial that gives them space to cope, have less recurrence and longer lives than those who react fatalistically or helplessly. It is less clear whether repeated negative experience or the repression of anger, frustration or other strong emotions can contribute to the onset of malignancy. The possibility that individuals may be able to ‘’give” themselves a disease, that conditions such as cancer or diabetes may be due to something they said, did or didn’t do, years beforehand, has generated feelings of guilt in patients. So far, there is no convincing evidence to link any ailment a patient may currently have with any changes in the immune system that resulted from a specific event in the past.
Diseases such as cancer are more likely to result from a complex interaction of genetic and environmental factors, including nutrition. Emotions probably play only a small part in determining susceptibility to serious diseases. Psychological factors can affect survival, but their influence seems relatively minor, especially in later and serious stages of the disease, or when the immune system is severely compromised, as in AIDS.
However, these factors could have a crucial impact on the quality of life and the severity of many chronic diseases. Given a particular set of circumstances, how a patient copes mentally with the stress of these conditions may be significant.