Immunosuppression

• Immunosuppression

  -stress can cause illness by preventing the immune system from working efficiently and carrying out usual task of identifying and destroying invading germs and foreign bodies.
• Stress affects the immune system:

  -Stress can supress the immune system directly.

  -E.g. cortisol produced by the hypothalamic pituitary adrenal stress response inhibits the production of lymphocytes.

  -High levels of adrenaline and noradrenaline in bloodstream appear to supress the immune system and linked to hypertension.

  -Indirect effects: lifestyle behaviours like smoking, drugs or disturbed sleeping habits have a detrimental effect on immune functioning.
• Keicolt Glaser et al - effects of the immune system

  -Aim: to establish a link between stress and reduced immune functioning. Based on assumptions that the body's response to stress decreases immune functioning.

  -Procedure: 75 students volunteered. The IV was naturally occurring (natural experiment) and repeated measures used when blood samples were taken one month before exam and first day of exam. The number of natural immune killers and T-cells were measured as indicators of immune functioning. Questionnaire was given both times and measured psychiatric symptoms and loneliness.
• Keicolt Glaser study

  -Results: Natural killer and T-cell activity did decline between lower and high stress conditions. Findings revealed immune response were supressed in PP who reported they were experiencing psychiatric symptoms loneliness and life changes.

  -Conclusion: shows stress is associated with immunosuppression and that the effect is stronger when there are multiple sources of stress. Association found not causation so can't conclude as it's not a true experiment. This supports importance of stress management in good immunosuppression.
• Evaluation - methodological issues

  -Use of self report, lacks internal validity as PP may lie to make them seem less stressed than they are so SDB can occur. This means it's not representative of whole population so lacks generalisability.

  -Association is found so no cause and effect relationship is established.

  -May be co-founding variables. Work, pressure from people and school can contribute to stress. Some people have more/less social support than others which means will be easier/harder to cope with stress.
• Evaluation - sample used

  -Volunteer sample was used. This method means it is easy to collect medical students to take part. However, bias sample as people who volunteer usually have similar characteristics and traits so not generalisable to target population as may have similar levels of stress.
• Evaluation - research by Keicolt Glaser are reliable

  -carried out another longitudinal study (13 months) in which they compared the health of two groups of people: caregiver looking after a relative with Alzheimer's disease and a matched group of non-caregivers.

  -They found that caregivers showed a weaker cell-based immune response than the control group.

  -This shows that more stress can weaken the immune functioning.