found following objective rather than subjectively rated stressful events and that immune
response varied according to the duration of the stressor and whether the stressor
involved an interpersonal or non social events. Given that stress can change health
behaviours (see above) it is possible that stress causes changes in the immune system by
changing behaviour. Ebrecht et al. (in press) examined this possibility, by assessing the
link between perceived stress and wound healing and controlling for alcohol consump-
tion, smoking, sleeping, exercise and diet. The results showed that stress was related to
wound healing regardless of changes in behaviour indicating that the stress–immunity
link may not be explained by an unhealthy lifestyle.
Research also indicates that stress may relate to illness progression. Kiecolt-Glaser
and Glaser (1986) argue that stress causes a decrease in the hormones produced to fight
carcinogens and repair DNA. In particular, cortisol decreases the number of active T-
cells, which could increase the rate of tumour development. This suggests that stress
whilst ill could exacerbate the illness through physiological changes. Such stress may
occur independently to the illness. However, stress may also be a result of the illness itself
such as relationship breakdown, changes in occupation or simply the distress from a
diagnosis. Therefore, if the illness is appraised as being stressful, this itself may be
damaging to the chances of recovery.
THE IMPACT OF CHRONIC STRESS
Most research describe to date has explored the impact of acute stress induced in the
laboratory or individual stressors such as life events. However, many people exist in a life
of ongoing chronic stressors including poverty, unemployment, job stress and marital
conflict. There is much research linking these social factors to health inequalities with
research consistently showing that psychological distress, coronary heart disease and
most cancers are more prevalent among lower class individuals who have more chronic
stress in their lives (e.g. Adler et al. 1993, 1994; Marmot 1998). However, untangling
this relationship is difficult as although chronic stressors such as poverty may cause
heart disease they are also linked to a range of other factors such as nutrition, hygiene,
smoking, social support which are also linked to health status. Furthermore, whereas
lower socioeconomic position is linked to chronic stressors such as poverty, higher
socio-economic position is linked higher perceived stress (Heslop et al. 2001). As a result
of these methodological problems many researchers have focused on specific areas of
chronic stress including job stress and relationship stress.
Job stress
Occupational stress has been studied primarily as a means to minimize work related
illness but also as it provides a forum to clarify the relationship between stress and illness.
Early work on occupational stress highlighted the importance of a range of job related
factors including work overload, poor work relationships, poor control over work and
role ambiguity. Karasek and colleagues integrated many of these factors into their job
demand–job control model of stress central to which is the notion of job strain (Karasek
STRESS AND ILLNESS 265