The Role of Stress in Illness

KEY STUDY- Williams et al (2000) anger and heart disease

Aim Investigate if anger is linked to heart disease Procedure 13,000 people did a 10 question anger scale including questions on if they were 'hot headed', if they felt like hitting something when angry or whether they got annoyed when not given recognition for good work. None of the participants had suffered heart disease at the start of the study. Findings 6 years later, health of the participants checked, 256 of the original sample experienced hart attacks. Those scoring the highest on anger scale were 2.5x more likely to have had a heart attack than those with those low anger ratings. Those who scored 'moderate' in anger ratings 35% more likely to experience a coronary event than those with a lower score. Conclusion Increased levels of anger (increased SNS activity) may lead to cardiovascular disease.

KEY STUDY- Kiecolt-Glaser et al (1984) Chronic stress & the Immune System

Aim To demonstrate that natural stressors could lower the immune system making people more likely to be ill. Procedure Took a blood sample from 75 first year medical students (49 males, 26 females), all who volunteer. Sample taken a month before the exams (baseline - low stress) and on the day of the exam (high stress). Index of immune functioning look at natural killer cell activity (NK) and part of natural immune system. Also complete Social Readjustment Rating Scale (SRRS) to measure other life stressors, also completed a 'loneliness scale' assessing how many interpersonal contacts they has (social network). Findings Immune system was reduced following the stressful exam. NK cell activity and killer T cell activity were significantly reduced in high stress samples in comparison to the baseline sample. Greatest reductions in students reporting high levels of social isolation. Found the immune system were weak in those experiencing other stressful life events. Conclusion Stress of the exam reduced the effectiveness of the immune system.

B Cells

B lymphocytes recognize antigens and become plasma cells that produce antibodies to fight them. B lymphocytes and T lymphocytes work together to fight infection.

T Cells (Memory & Killer Cells)

Cytotoxic T cells, often called killer T cells, destroy cells in your body that have been infected with an antigen, cancer cells, and foreign cells like transplanted organs. Helper T cells direct the immune response of B cells and other T cells. Regulatory T cells suppress your immune system to keep its response in check. In addition to preventing autoimmune disease, they also prevent other white blood cells from fighting real or perceived antigens.

Evaluation- Real Life Application (STRENGTH)

Dharbhar's research may eventually lead to patients being given low doses of stress hormone (cortisol) before surgery to help aid a quick and full recovery. Keicolt- Glaser also discovered students who took relaxation training during the exam period had better immune system function than those who didn't. This highlights the real life benefits of prevention techniques for chronic stress and helping maintain a well functioning immune system.

Cardiovascular Disorders (CVDs)

Evidence that stress may contribute to the development of various cardiovascular disorders like heart disease and strokes. Appears stress has both immediate (acute) and long terms (chronic) effects on the cardiovascular system. Adrenaline increases heart rate and causes the heart to work harder taking its toll over time. Constriction of the blood vessels causing them to eventually wear away. Increased pressure can also dislodge plaque on the walls of the blood vessels which can lead to blocked arteries and may cause heart attacks.

Evaluation- Some stress can benefit the Immune System (STRENGTH)

In some cases acute stress can benefit the function of the immune system and the human body. Dharbhar subjected rats to mild stressors and discovered that it was enough to stimulate a substantial immune response. Body prepared itself for potential physical damage by flooding blood stream with lymphocytes, protecting the body from potential antigens. Extrapolating the findings from rats to humans is problematic as humans are believed to be more physically and cognitively advanced, making comparison between the two difficult.

Natural Killer Cells (NK)

Kill virally infected cells and detect and control early signs of cancer. Protect against disease, specalised NK cells are also found in the placenta and may play an important role in pregnancy.

Immune System

Provides a defensive barrier against invading germs and foreign bodies (antigens) without it we would be very ill.

White Blood Cells (lymphocytes)

Part of your immune system system, helps the body fight antigens that make you sick. Your bone marrow constantly produces lymphocytes, some enter the blood stream and must go through your lymphatic system, leg, spleen, tonsils + lymph nodes.

Evaluation- Nomothetic VS Idiographic (WEAKNESS)

Research investigating stress effects usually takes a nomothetic approach (make general laws). However, evidence suggests there are individual differences in cardiovascular effects. Rozanski discovered the sympathetic branch of the autonomic nervous system in some is more reactive than in others. Shows that some respond to stress with greater increases in blood pressure and heart rate which would lead to more damage being caused. Findings suggest stress doesn't have the same effect for all individuals, therefore some researchers can be criticised for adopting a nomothetic approach and overlooking differences,

Evaluation- Methodology of research into effects of stress on Immune System (WEAKNESS)

Researchers used lab based studies to assess the relationship between stress and the immune system using artificial stressors such as electric shocks that can be easily manipulated and controlled in the settings used. However, this may not reflect the true effect of real life stressors such as exams, which means the use of artificial stressors may lead to low external validity. Although, level of control in such research can be easily replicated to support previous findings, meaning that the research supports psychology's scientific status.

Immunosuppression

Stress can suppress the immune system directly, E.g. the release of cortisol in the HPA (HYPOTHALAMIC PITUITARY SYSTEM) can inhibit production of lymphocytes. Indirect effect: can influence behaviours people carry out to reduce stress they feel. E.g. they may smoke, drink or have difficulty sleeping, all of which have a detrimental effect on a persons health.