SUMMARY
A number of personality traits show significant relationships with various health out -
comes such as morbidity and mortality. Indeed some of these relationships are of a similar
size to those reported for more well-known risk factors like blood cholesterol levels.
Of the Big Five personality traits that form much of the focus in modern-day
personality research there is good evidence relating low levels of neuroticism and high
levels of extraversion and conscientiousness to health outcomes (e.g. lower levels of
illness and greater longevity). Evidence also suggests that optimism is positively related
to health outcomes, while type A behaviour and hostility (low agreeableness) tend to
be negatively related to health outcomes. In some cases (such as type A and type D)
recent studies have shown declining effects and the importance of such variables remains
a controversial issue.
The explanations of these relationships between personality and health are many
and varied. They range from artefactual explanations, through mediating mechanisms,
to direct biological or physiological effects. So, for example, much of the observed
impact of neuroticism on self-reported illness is probably attributable to those higher in
neuroticism being more likely to report symptoms. In relation to conscientiousness and
health, for example, there is evidence of a mediating mechanism through greater engage -
ment in health-protective behaviours and less engagement in health-risking behaviours,
whereas in relation to hostility there is evidence of a direct effect through damage to
arteries caused by over-reactivity to stress among those high in hostility. Detailing the
range of effects that different personality dimensions can have on health and assessing
the explanations of these effects is an exciting area of current research in health
psychology.
PERSONALITY AND HEALTH 135TABLE 6.2Explanations of the relationship between personality traits and health
outcomes
Non-causal explanations
Causal direction problem Health outcome causes personality change (e.g. illness affects
perceptions and behaviour)
Third variable problem Both the personality trait and health outcome are caused by
another underlying variable (e.g. disease)
Measurement artefact The measurement of the health outcome is contaminated by the
personality trait
Causal explanations
Physiological changes The personality trait causes physiological changes that in turn
influence health outcomes
Tropisms The personality trait means the individual is more likely to be
exposed to risky situations
Health behaviours The personality trait makes the individual more likely to engage
in health-risk behaviours and less likely to engage in health-
promoting behaviours
Stress impacts The personality trait makes the individual more likely to
experience stress and/or less likely to be protected from the
effects of stress through coping mechanisms or social support.