The immune system is made up of cells and chemicals that seek and destroy bacteria and viruses. When someone is experiencing a stressful situation, all the body’s resources are diverted and this suppresses the immune system by stopping the production of white blood cells-lymphocytes. Over a long period of time, (a long-term stress response), the person’s immune system stops functioning properly and is left open to infection. Long-Term stress can affect the cardiovascular system.
Short-term stress involves the suppression of the immune system, known as immunosupresssion- as part of the need to divert all resources into coping with the emergency. Various studies have been devised to test whether stress makes us more vulnerable to infection and illness. Research on both humans and animals has supported the theory that stress can reduce the effectiveness of the immune system.
Brady et al’s study of stress and the development of ulcers showed that monkeys being given electric shocks, every 20 seconds in 6 hour sessions, proved that the ‘executive’ monkeys-who pushed the lever to delay shocks- would develop illnesses and later die. Brady’s findings showed that the ‘executive’ monkeys were more likely to develop an illness (ulcers) and later die. The illness and death was not due to the shocks, but due to the stress that the executives felt by trying to delay/avoid them. In the long-term, this stress reduced the immune system’s ability to fight illness.
However, there were ethical considerations that could have been questioned in Brady et al’s study. The experiment was very cruel to the monkeys and would not be allowed by the BPS today. Also, it is hard to generalise findings from animals to humans. In addition, it is known that people with no/little control over their own lives experience high levels of stress- that this research does not explain. Nonetheless, studies of stress on the immune system have also been carried out on humans and support the theory of immunosupresssion.
Kiercolt-Glaser et al 1987 pioneered the study of immune function in people exposed to high levels of stress. Glaser said that although people do not show obvious illness (due to their stress), many people have immunosupresssion. Glaser’s study aimed to find out whether people who have chronic stress have lower immune system functioning, and also, are they more vulnerable to illnesses? Glaser took a sample of people who were carers for Alzheimer’s patients as they had a very stressful responsibility.
Glaser compared an Alzheimer’s carers’ group to an age-matched control group. They measure the activity of their immune system from blood samples. They also measured how long it took for their body tissue to repair fro a minor arm wound. The results showed Alzheimer’s carers’ had higher levels of depession and it took them longer to recover from the wound. Also, they showed significant immunosupresssion.
The findings of Glaser’s research suggested that the study was unethical. He would have to tell the carers that they were more likely to die. In Brady’s study, the monkeys cannot communicate, yet it was still unethical to use them and for them to die because of the experiment. Whereas Brady’s study used animals, Glaser used humans and you cannot extrapolate from the findings. This is positive as animal death is prevented. Glaser used interviews in his study. There are flaws to using this research method; people can lie, thus results are unreliable, they can withhold information or, conversely, exaggerate it for social desirability. By using interviews the cause and effect of the study cannot be established, it is simply a relationship between two variables.