role of stress in illness

• Immune system suppressed


  Directly - cortisol produced by the hypothalamic-pituitary-adrenal system (HPA) inhibits production of immune cells

  Indirectly - stress influences lifestyle behaviours (smoking, drinking) that have a negative effect on immune functioning
• Chronic stress of exams - decrease in NK and killer T cells


  - Kiecolt Glaser et al (1984) tested 75 medical students before the exam period (low stress) and on the day of the first exam (high stress). Students also completed questionnaires measuring sources of stress and psychological symptoms

  - the activity of natural killer (NK) and killer T cells decreased between first and second samples - evidence of an immune response suppressed by a chronic stressor

  - decline was greatest in students who reported feeling lonely and experiencing other sources of stress e.g. life events
• Chronic stress of caring for ill relative - increase in immune antibodies


  - Kiecolt Glaser et al (1991) compared caregivers (looking after a relative with Alzheimer's) with a matched group of non-caregivers

  - over 13 months caregivers bad weaker cell-based immune response compared with control participants

  - caregivers also had more infectious illnesses and higher levels of depression (32% 9; caregivers; 6% of control group)
• limitation


  P - research shows stress can be protective

  E - stress can have immunoenhancing effects e.g. Dharbhar (2008) exposed rats to mild acute stressors which stimulated a major immune response

  E - immune cells e.g. lymphocytes flooded into bloodstream and body tissues to protect against acute stress - chronic stress may be more damaging

  L - this suggests that the relationship between stress, the immune system and illnesses is complex and not yet fully understood
• strength


  P - research into stress and illness may have real world application

  E - Dharbhar's research could lead to patients getting low doses of stress hormones before surgery to improve recovery

  E - students who took a relaxation programme seriously had better immune functioning during exams (Kiecolt-Glaser and Glaser 1992)

  L - these applications benefit real people and confirm the relevance of stress to the immune system
• strength/weakness


  P - research methods

  E - lab experiments measure the effects of acute stressors while controlling confounding variables - can establish causation

  E - however, lab experiments are unlike real world stressful situations and also feature demand characteristics

  L - therefore, lab experiments are useful for establishing the apparent causes of immunosuppression, but they may not actually be causes in the real world
• stress associated with CVDs

  - CVDs are disorders of heart and blood vessels - including coronary heart disease (CHD) and stroke (blocked blood vessels in the brain)

  - acute stress leads to high levels of adrenaline with direct and continuing effects on heart muscles e.g. increased heart rate
• acute stress caused by watching football match

  - Wilbert-Lampen et al (2008) looked at incidences of heart attacks during football matches (sudden emotional arousal - an acute stressor) played in Germany during the 1996 World Cup

  - on days Germany played, cardiac emergencies increased by 2.66 times compared with a control period - acute emotional stress of watching favourite football team more than doubled participants' risk of a cardiovascular event
• chronic stressors e.g. workplace stressors

  - Yusef et al's (2004) interheart study compared 15,000 people who'd had a heart attack (myocardial infarction) with a similar number of people who had not

  - several chronic stressors had a strong link to MI including stressful life events and workplace stress - role of stress greater than obesity and third behind smoking and cholesterol
• limitation


  P - effects of stress on CVDs are mostly indirect

  E - the evidence for stress as an indirect factor in CVDs is much stronger than evidence that it directly causes CVDs

  E - Orth-Gomer et al (2000) found that marital stress tripled the risk of heart attack in women who already had CVD - different from causing CVD

  L - this suggests that stress increases vulnerability to CVD, mainly through indirect effects e.g. lifestyle
• strength


  P - research to support the link between stress and CVDs

  E - Song et al (2019) compared people diagnosed with stress-related disorders to their unaffected siblings and members of the general population

  E - people with stress disorders had a 64% greater risk of a CVD in the first year after diagnosis

  L - this shows that exposure to chronic psychological stress can significantly increase CVD risk
• strength/weakness


  P - what's the cause?

  E - the cause of CVDs could be psychological - stress triggers a physiological response that damages the cardiovascular system e.g. heart muscle

  E - however, the cause could be psychological e.g. personality some people perceive stressors negatively and have a strong physiological reaction

  L - this suggests that while physiology may be the immediate direct cause of CVDs, the real cause is psychological