role of stress in illness Flashcards
what is immunosuppression?
the ability of stress to cause illness by preventing the immune system from working efficiently + carrying out its usual tasks of identifying/destroying invading pathogens
how did Kiecolt-Glaser measure stress in medical students?
~ blood samples were taken from 75 first-year medical students
~ sample 1 = 1 month before their finals
~ sample 2 = on the day before their finals
what did Kiecolt-Glaser find from the blood tests of medical students?
there were less natural killer (NK) cells in the second sample, confirming that stress is associated with reduced immune efficiency
what did Kiecolt-Glaser find from the questionnaires of medical students?
immune system was less effective in those who reported feeling lonely + experiencing major life events
what was the sample in Kiecolt-Glaser’s second study?
~ 13 women who cared for relatives with dementia
~ a control group of 13 women who were not carers
how did Kiecolt-Glaser measure stress in carers?
~ participants were given a punch biopsy (3.5mm cut below elbow)
~ participants were also given a 10-item perceived level of stress scale to check how stressed they really felt
how did Kiecolt-Glaser assess time taken for wound to heal in the carers study?
time taken for the wound to heal was assessed by photographing it regularly + observing response to hydrogen peroxide
what did Kiecolt-Glaser find from the stress scale + punch biopsy in the second study?
~ wound healing took about 9 days longer in carers than in non-carers
~ carers had lower levels of cytokines (which help speed up wound healing)
~ carers reported much higher stress than non-carers in the stress scale
what is one limitation of research into immunosuppression?
they use weak research methods
give 3 examples of weak research methods in Kiecolt-Glaser’s studies
~ lab experiments - high control means that they are unlike real-world stressful situations
~ demand characteristics - participants may only behave how they think the researchers want them to
~ students knew about upcoming exams - the first study doesn’t show how immune system may react to unexpected stressors
how has Kiecolt-Glaser’s research had a real-world application regarding students/exams?
follow-up research has shown that students who took a relaxation programme seriously had better immune functioning than those who didn’t bother with it
how does Dharbhar’s research contradict Kiecolt-Glaser’s research?
~ his research showed that stress can make illness LESS likely
~ he subjected rats to mild acute stressors + found that immune cells flooded to bloodstream/body tissues in order to prepare for damage
~ this shows that acute stressors may not have the same immunosuppressive effects as chronic stressors
how could Dharbhar’s research into immunosuppression have a real-world application?
his research could lead to patients being given low doses of stress hormones before surgery
how can stress lead to cardiovascular disorders?
- activation of sympathetic branch of ANS leads to an increase in adrenaline
- high levels of adrenaline increase heart rate, which can cause further strain on the heart - this can lead to high blood pressure
- high blood pressure causes blood vessels to wear away + plaque to be dislodged onto artery walls
- plaque can cause blocked arteries, which may lead to heart attacks/strokes
how did Wilbert-Lampen research acute stress?
they looked at examples of heart attacks in German football supporters during matches played in the 1996 World Cup
what did Wilbert-Lampen find?
on the days when Germany played, cardiac emergencies increased by 2.66 times compared with a control period
how did Yusuf research chronic stress?
~ they examined chronic stressors in an investigation involving 52 countries, to identify major risk factors for CVD across different cultures
~ they compared 15,000 people who had had a heart attack with a similar number of people who had not
what did Yusuf find?
they found several chronic stressors with a strong link to heart attacks, including workplace stress + stressful life events
what did Yusuf conclude?
~ the contribution of stress to CVDs was greater than the contribution of obesity
~ stress contributes to the worsening of existing disorders
what is one strength of research into CVD?
there is extra research support
what did Song et. al. research? (research support for CVD)
they identified more than 130,000 people with stress-related disorders and compared them to a control group of unaffected siblings + 1 million people with no stress-related disorder
what did Song et. al. find?
compared to the controls, people with a stress-related disorder had a 64% greater risk of CVD
what is one limitation of research into CVD?
it’s hard to differentiate between direct + indirect effects of stress on CVD
how do indirect effects of stress lead to CVD?
it is more likely that when we engage in behaviours to RELIEVE stress, these indirect effects are more likely to cause CVD than the stress itself (e.g. when stressed we may eat more fatty food, smoke/drink more - these behaviours cause CVDs indirectly)
