When the head overrules the stomach

Pain in your stomach? Did you know that intense stress can make your digestive system switch off? Interactions between head, stomach and gut are being paid more and more attention, and a research group at the University of Bergen is trying to find out whether negative experiences in childhood may lead to stomach problems when we grow up.

For hundreds of years we have known that there are very close links between the head and the stomach. But what really happens when mental stress causes stomach problems?

Can the causes lie in our childhood, in how we learned to cope with stress as children? Is very early experience the decisive factor? Such questions, under the name of "psychobiological risk factors", are being systematically studied by an interdisciplinary network of scientists led by Professor Robert Murison of the Dept. of Biological and Medical Psychology at the University. The network was launched on the initiative of the Research Council of Norway's Mental Health Programme, and consists of researchers in Oslo and Bergen as well as in other countries. The project's main target group consists of patients with intestinal inflammation. However, its long-term aim is to acquire more knowledge of the relationship between the head/brain and gastrointestinal systems in general.

Professor Murison claims that the gastrointestinal system is one of the most sensitive in the human body. Exposure to extreme stress, for example, has an instant effect on this system.

"An alarm response is triggered in people who feel threatened", he says. "Just think how we "gasp" when we see a near-accident . The body's alarm system takes resources from inessential functions such as digestion, and stops the stomach from functioning for a while. Energy is transferred to other systems until the threat has disappeared. Then something happens in the stomach, whose activity is turned on again".

Professor Murison points out that interestingly enough, this applies only to the upper regions of the digestive system, while the activity of the large intestine actually increases.

Some of us are unable to turn off this alarm response, and such people live in a more or less continuous state of high activation. The network hopes that its research will lead to better understanding of this mechanism in such people.

Healthy stress

Murison, who is a psychobiologist, is leading a triple set of animal experiments with which he hopes to map out the relationship between stress and coping. The research group follows the same individuals through successive life stages in order to find out which of them will develop a psychological disposition to develop disorders of the gut. The team is working on the hypothesis that people who have experienced and coped with stress in childhood will be more able to deal with stress as adults.

"The stress that the body can deal with is healthy and necessary, while people who have experienced stress without being able to overcome it can experience problems. Coping with stress can also be difficult for individuals who have never experienced stress to any extent", says the professor.

Part 1 of the study has just come to an end; it showed that stress increases sensitivity to stomach problems. The researchers have also shown that stress also affects the likelihood of suffering inflammation of the gut. Last Autumn, Murison was awarded the prestigious Pavlov Prize for these results.

Away from mother

Part 2 of the study is a continuation of some work done by American researchers, who separated baby rats from their mothers for 15 minutes a day, until they were independent (about 21 days old). It turned out that such a mild stress made them less anxious in challenging situations - i.e. they were more capable of tackling stress. The next step was to remove the baby rats from their mothers for three hours a day. When they did this, the researchers found that the rats subsequently became extremely stressed when they were presented with unfamiliar tasks.

Murison's group is now on the point of continuing these experiements with baby rats in order to find out how stress affects the development of inflammation of the gut in adulthood. The researchers will induce inflammations in order to measure how long it takes before symptoms appear, and how long until they disappear again. The point is to find out whether this is affected by early experience.

"What happens very early in life has enormous long-term effects. In research on the gastrointestinal system, it is natural to ask how early experience affects our susceptibility to disease", says Professor Murison. He mentions an irritable gut as an example of a condition that many doctors and psychologists believe may be due to trauma early in life. If the experiments demonstrate a higher rate of inflammation of the gut in individual who have suffered "childhood trauma", the third phase of the study will look at whether this tendency can be reversed by means of techniques for coping with stress. This phase is due to start in 2002, when Murison's group will cooperate more closely with groups doing clinical research at Haukeland Hospital and the Rikshospital in Oslo. These hospitals will employ methods that aim to improve the ability of patients to cope with stress.

Coping strategies

"How can the results of research on animals be transferred to people?"

"Coping strategies are species-specific, and the results cannot therefore be transferred directly from one species to another, but the concept of coping itself can be utilised with regard to all species. The advantage of animal experiments is that they can teach us things that we cannot learn by using human beings. Most human studies are retrospective; i.e. we have a patient, and we ask ourselves what factors might have caused a particular illness in that patient. When we use animals we can work in the opposite direction. We can add variables and see how the animal reacts to them. For example, is there a difference between solitary animals and those living in company with others".

Murison believes that animal experiments can be useful if they tell us whether psychological factors have any influence on the return of intestinal inflammation. Knowing this will enable us to look at patients' coping strategies, and tell us whether cognitive therapy might help, for example.

"As far as inflammation of the gut is concerned, it is essential to remember that this condition has many causes, including physiological ones. At the same time, stress may be the direct cause of physiological changes in the gut, and in such cases it is important to reverse the stress situation".

"We know that the development of erosions, i.e. changes in the gut, are most likely to take place during the period immediately following stress. When the stress ceases, there is a reaction", says Murison. He adds that the pyschological factor is important not only for susceptibility to disease, but also for how long it takes to become well again.

Holism

The Professor believes that it is important to treat patients from a more holistic perspective, pointing out that psychological effects on the body are beginning to be given more sympathetic understanding by the medical profession.

"Since the war the image of medicine has been one of white coats and high technology. The patient has been treated as an object, and the mental aspect has tended to be forgotten.Now, however, it has been well documented that psychological factors are important as far as both the frequency and prognosis of disease are concerned".

There is a relatively high rate of gastrointestinal disease in Norway.

This may be due to genetic, dietary or other lifestyle factors and it is possible that doctors focus on such factors - so that we end up in a vicious circle - with the possibility of overdiagnosis, says professor Robert Murison, who is working on problems of the stomach and gut.