Discuss the possible effects of stress on the immune system.

Psychology-Mrs Scarlett

Discuss the possible effects of stress on the immune system (18 marks)

Seyle (1956) was the first person to propose a relation between stress and the immune system and he called this connection the General Adaptation Syndrome (Gas). The exhaustion stage is the last part of the GAS and this is when stress is at its maximum. In this stage all of the body’s resources are diminished due to failure of the resistance stage. This causes the person to become irritable, unable to concentrate and the immune system collapses; therefore stress-related diseases become more likely which may conclude in death. This last stage proposes a major link between stress and the effects it has on the immune system.

The GAS theory is fairly reliable as this has furthered our understanding of stress and it has become very useful in predicting physiological responses to stress. The GAS also provides a useful model of the cause of physical injuries and illness when stress is prolonged. However the GAS had its limitations. Most of Seyles work was based on rats so the research is very restricted, and it may not apply to other animals including humans. There is overemphasis on the physiological responses to stress and the model does not take into consideration that there are other human cognitive factors such as personality, which suggest that person’s capability to stress. The model also implies a passive response to stressors, despite the fact that people react differently to the same stressor and the reaction depends on the individual, the situation and the particular source of stress.

Another key study was by Kiecolt-Glaser et al (1984) and they investigated whether under naturally occurring stressful situations participants’ immune system functioning would decline. They did this by taking blood samples from 75 first year medical students all of whom were volunteers. The samples were taken one month prior to their final examinations, and again on the first day of their final exam, hence the stress sample. This research found that natural killer cell activity declined between the two samples. Immune System responses were found to be especially weak in students who reported being lonely or were suffering form ...

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There were many strengths to the study. It was a natural experiment; therefore there were fewer ethical objections. The independent variable chosen was good, as it is a long-term form of stress. However there were also many criticisms of this study. With it being a natural experiment, it lacked validity and therefore was not necessarily accurate. The cause and effect cannot be stated from this study. We can only state that there is a negative correlation between stress and immune responses. The immune system is very complex therefore the quality of an individual’s immune system is hard to assess. Modern research by Evans, Clow and Hucklebridge (1997) discovered the assumption of stress suppressing the immune system, to be oversimplified.

Cohen et al (1993) did a study to measure the amount of stress in 154 men and 266 women volunteers. He measured it by a life event scale covering the previous year, a perceived stress scale, assessment of the individuals own perception on the levels of stress in their lives and a negative effect (emotion) scale. They also measured levels of anxiety, fear, depression and irritation. The experimenters combined scores on the three scales to produce a psychological stress index for each person. They then exposed the volunteers to nasal drops containing respiratory viruses and used blood measures and clinical observation for the following six days to see whether respiratory tract infections for example, colds developed. A difference was found between groups with low scores on the stress index, and those with high scores, were highly stressed participants who developed a significant amount of colds. This study clearly shows that stress increases vulnerability to infectious diseases using direct measures to isolate cause-effect relationships.

Another form of illness, which is made more vulnerable by stress, is Asthma. Asthma is a disease, which involves both external and internal factor. It is the internal factor that is most affected by acute effects of psychological stressors. Studies have shown that children with chronic asthma improve considerably when away from their parents. The changes may have resulted from removal of an interaction that produced frequent stressful situations. In 1974, Liebman et al successfully used family therapy to treat severe and chronic asthma in seven out of seven children. Additionally, asthmatics exposed to a harmless substance that they thought they were allergic to elicited a severe attack (Elliott & Eisdorfer, 1982). Even more importantly, interactions between antigens and immunoglobulin E antibodies lead to the release of histamine, which blocks airways, and other mediating agents. When antigens have an easier time invading the body, as they do under stress, the number of such interactions increases considerably.

In conclusion there is a significant relationship between stress and the immune system. Evidentiary support for this statement comes from Seyle, Kielcot-Glaser et al, Cohen et al, Liebman et al and Elliot and Eisdorfer. They each contributed an experiment to show that the relationship exists and they found similar results in each experiment. However not all of these experiments were completely reliable as they had their limitations. Therefore more needs to be done before it is absolutely certain that stress causes illness and also further research is needed to clarify exactly how stressors contribute to each of these problems, so that treatment can be given to protect the body from these diseases.