Download KEY STUDY: Stress and The Immune System (Kiecolt

KEY STUDY: Stress and Immune
Function – Kiecolt-Glaser (1995)
To demonstrate the direct effects of stress on the immune system by looking at how quickly
wounds heal.
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A matched participant design experiment was used
Participants were recruited using advertisements in newspapers (therefore a volunteer
sample)
13 women aged 47-81 years were carers (caring for relatives suffering from senile
dementia) and placed in the experimental group.
A further 13 were matched with carers on the basis of age and income but not marital
status – this was the control group.
All participants were given a wound – a ‘punch biopsy’ which is a cut of 3.5mm just
below the elbow.
The wounds were dressed and treated by a nurse in the same way for each participant
A second measure of immune response was taken – researchers assessed levels of
cytokines – chemical substances involved in the stress response
Participants were given a 10-item perceived stress scale to check how stressed they
actually did feel
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Complete wound healing took significantly longer in the carers than the controls. It
took an average of 9 days (24% longer) in the carers
Cytokine levels were lower in the carers than the control group
On the perceived stress scale, carers indicated that they were feeling more stressed
These findings offer support for the view that chronic stress depresses the functioning
of the immune system – because wound healing was slower in the individuals that
experienced chronic stress
Lower levels of cytokines in chronically stressed individuals supports the view that
stress lowers immune response directly
These findings have important implications for treating people with infections,
particularly where people are recovering from surgery. Therefore it would be important
to reduce stress as far as possible in patients to speed their recovery
The matching of participants was inexact e.g. more of the carers were married and
were non-smokers. However, both of these variables are related to lower stress.
Social support is known to reduce stress and non smoking is related to better immune
functioning. Therefore this sample bias would suggest that carers, if anything, should
have better immune functioning. This strengthens the validity of the findings of this
study.