The Role of Stress in Illness (AQA A Level Psychology): Revision Note

Immunosuppression

• The immune system comprises cells, mainly white blood cells (leucocytes), travelling through the bloodstream to defend the body against antigens (foreign substances), like bacteria, viruses and cancerous cells 

• Many of these leucocytes secrete antibodies which bind to antigens and destroy them

• Immunosuppression is the suppression of the body’s immune system by the hormone cortisol, which is produced in the adrenal cortex through the activation of the HPA when subject to a chronic (ongoing) stressor

• Stress does not actually cause infections, but with chronic stress the immune system’s ability to fight off antigens is reduced and infection becomes more likely

• Infection becomes more likely because when cortisol is produced continuously, it interferes with leucocyte activity and the production of antibodies

• This reduction in the immune system’s ability to fight off infection when under chronic stress is thought to be why many people get a cold around exam time

Cardiovascular disorders

• The fight-or-flight response to stressors results in an elevated heart rate 

• The elevated heart rate  causes faster blood flow through arteries which, combined with potential blood thickening, may lead to the collapse or blockage of artery walls 

• When the arteries of the heart are obstructed or damaged, it impairs the heart's function, potentially resulting in heart attacks or other cardiovascular problems

• Cardiovascular disorders may also result indirectly from stress, through the stressed person’s coping mechanisms, such as smoking or drinking alcohol, both of which may cause cardiovascular disease

Research which investigates the role of  stress in illness

• Kiecolt-Glaser et al. (1995) inflicted small wounds on participants and measured how long they took to heal, finding that  healing took longer in women who cared for dependent elderly relatives, suggesting that chronic stress reduces immune system functioning

• Melamed et al. (2006) reviewed clinical evidence and discovered that prolonged exposure to work-related stress was associated with increased levels of cardiovascular disorders, due directly to immunosuppression and blood clots and indirectly to poor health behaviours, such as excessive drinking

Evaluation of the Role of Stress in Illness

Strengths

• Research supports the theory that chronic stress is correlated with immunosuppression and cardiovascular disorders

• Physical changes in the body of people suffering chronic stress, such as levels of stress hormones, leucocyte numbers and heart rate and blood pressure, are measured objectively, which increases the reliability of the data

Limitations

• Cause-and-effect cannot be determined, as other factors e.g. unhealthy lifestyle, smoking and drinking, may also be contributory factors to immunosuppression and cardiovascular disorders

• It is impossible to identify specifically which factors are most important in the development of immunosuppression and cardiovascular disorders, as particular stressors cannot be manipulated experimentally to test their effect

Issues & Debates

• The role of stress in illness is often explained in terms of biological mechanisms (e.g., HPA axis, cortisol, immune suppression), reducing complex behaviours to hormones and physical responses

  • This ignores social, psychological and lifestyle factors (e.g., sleep, diet, smoking), which also impact immunity and heart health

• Research into stress and illness uses the nomothetic approach, aiming to establish universal biological laws about how stress affects the immune and cardiovascular systems

  • This allows psychologists to make general predictions about health outcomes but may overlook individual differences in coping strategies and stress resilience