Human research
Human models have also been used to examine the effect of control on the stress–illness
link. For example, the job strain model was developed to examine the effects of control on
coronary heart disease (e.g. Karasek and Theorell 1990). The three factors involved
in the model are (1) psychological demands of the job in terms of workload; (2) the
autonomy of the job, reflecting control; and (3) the satisfaction with the job. This model
has been used to predict coronary heart disease in the USA (Karasek et al. 1988), and in
Sweden (Karasek et al. 1981). The results of these studies suggest that a combination of
high workload (i.e. high demand), low satisfaction and low control are the best predictors
of coronary heart disease.How does control mediate the stress–illness link?
A number of theories have been developed to explain how control influences health and
mediates the stress–illness link.
Control and preventive behaviour. It has been suggested that high control enables the
individual to maintain a healthy lifestyle by believing ‘I can do something to prevent
illness’.
Control and behaviour following illness. It has also been suggested that high control
enables the individual to change behaviour after illness. For example, even though
the individual may have low health status following an illness, if they believe there is
something they can do about their health they will change their behaviour.
Control and physiology. It has been suggested that control directly influences health
via physiological changes.
Control and personal responsibility. It is possible that high control can lead to a feeling
of personal responsibility and consequently personal blame and learned helplessness.
These feelings could lead either to no behaviour change or to unhealthy behaviours
resulting in illness.The possible benefits of low control
Most theories of the relationship between control and stress suggest that high control
(such as predictability, responsibility, etc.) relates to a reduction in stress and is therefore
beneficial to health. However, in certain situations a perception of low control may
result in lowered stress. For example, flying in a plane can be made less stressful by
acknowledging that there is nothing one can do about the possibility of crashing. To an
extent this perception of helplessness may be less stressful than attempting to control
an uncontrollable situation.CONTROL AND SOCIAL SUPPORT IN STRESS AND ILLNESS
Haynes et al. (1980) carried out a study to examine the interrelationship between
perceived control and social support and their effects on the stress–illness link. They280 HEALTH PSYCHOLOGY