Cohen et al. (1993)
Cohen et al investigated the role of general life stress on vulnerability to the common cold virus. 394 participants completed questionnaires on the number of stressful life events they had experienced in the previous year. They also rated their degree of stress and thier level of negative emotions such as depression. The three scores were combined into what Cohen et al. called a stress index.
The participants were the exposed to the common cold virus, leading to 82% becoming infected with the viruse. After 7 days the number whose infection developed into clinical colds was recoreded. The findings were that the chance of developing a cold was significantly correlated with stress index scores.
Cohen et al. concluded that life stress and negative emotions reduce the effectiveness of our immune system, leaving…