394 P's completed questionnaires on number of stressful life events they had experienced in the previous year.
They also rated their degree of stress and their level of negative emotion such as depression.
The 3 scores were combined and called a stress index.
The P's were then exposed to the common cold virus.
82% became infected with the virus.
After 7 days Cohen et al. recorded the number of participants whose infection had developed into the clinical cold.
They found that the chance of developing a cold was coreelated with stress index scores.
The concluded that life stress and negative emotions reduce the effectiveness of the immune system leaving ppl less able to resist viral infections.
METHODOLOGICAL AND ETHICAL ISSUES
Indirect study in that there were no direct measures of immune function. However, supported by Evans and Edgington.
Does not tell us which element of stress index is most important.
P's should be in good health prior to study.
Fully informed consent with debriefing after.
P's should be consistently monitored to check for any reactions to viral challenge.
Balanced against any psychological or physical distress.