Smith & MacKenzie (2006). Personality and risk of physical illness – Article summary

A lot of personality constructs have been used as predictors of health which poses challenges for the interpretation and integration of findings. The measures often have poor psychometric properties. This problem can be addressed by using the five factor model of personality (FFM). This includes measurements that have been assessed for their psychometric properties. FFM helps assess which personality traits predict health but does not determine how these personality traits predict and influence health.

The social-cognitive tradition describes personality through the content of personality characteristics (e.g. schemas, scripts). Associations between personality traits and sociocognitive characteristics can identify mechanisms through which traits influence affect and behaviour. This could illuminate mechanisms through which personality characteristics influence health. It is possible that consistency in personality is better captured at the level of patterns of behavioural response to variation in specific types of situations rather than the broad traits and aggregated behaviour. It is thus important to look at the situations in which people show certain behaviour.

Personality traits appear to influence exposure to health-relevant social circumstances rather than simply moderate reactions to this purportedly separate class of influences on health. The distinction between person characteristics and social environmental factors is thus artificial.

The interpersonal approach to personality assumes an inherent association between personality and social circumstances. It describes the ways in which people shape and are shaped by the social contexts they encounter (i.e. transactional cycle). Intraindividual factors (e.g. expectancies, goals) guide overt social behaviour. This leads people to behave in a way consistent with these factors (e.g. positive people behaving positively so others do so too, reinforcing their view). This leads to stability of reciprocal interaction patterns. The interpersonal approach influences an individual’s exposure to potential stressors and the degree of stress-reducing social resources. This makes that personality can influence the frequency (1), magnitude (2) and duration of exposure to stressors in daily life (3).

According to the interpersonal approach, social behaviour can vary along the dominance versus submissiveness dimension and the friendliness versus hostility dimension. This is called the interpersonal circumplex. Agency refers to striving for separateness (1), achievement (2) and power (3). Communion refers to striving for connection (1) and concern for others (2).

Social-cognitive models state that personality and social situations are reciprocally related.

Self-reports of illness or health status is likely to include systematic variance that is unrelated to actual health. It can therefore be more useful to use objective markers for health (e.g. verifiable disease). The association between personality and health can be tested using cross-sectional designs, although a cross-sectional design with a latent disease state is more effective, as the personality is less likely to be a psychological reaction to the disease. Personality traits may influence subsequent disease through health behaviour (e.g. smoking) or biological consequences of psychological stress.

Personality influences health-relevant daily habits (e.g. exercise). This could mediate the association between personality and subsequent disease. The interactional stress moderation model specifies physiological rather than behavioural mechanisms. It suggests that personality influences the appraisal of potentially stressful life circumstances as well as coping responses. This, in turn, influences the physiological response to stress.

Constitutional predisposition models describe a non-causal association between personality and health. According to this view, an underlying genetic or other constitutional factor produces both a physiological vulnerability to disease and the behavioural, emotional and cognitive phenotype of personality. In the illness behaviour model, personality influences perception of and attention to normal physiological sensations (1), the labelling of such sensations (2), the reporting of symptoms (3) and the use of health care (4). However, personality does not influence the actual disease according to this model.

Individuals with type A personality show larger cardiovascular and neuroendocrine responses to a variety of stressors. It is also possible that people with a type A personality select more challenging tasks and often evoke competitive and antagonistic behaviour from others. Hostility, more often found in type A personality, is associated with an increased risk of CHD (i.e. disease). Hostility and anger might play a role across the development and course of the condition. The effects are stronger and more consistent for the initial development of disease as compared to its course. Anger and hostility also predict the development of hypertension and stroke.

Hostile individuals are seen as responding to potential stressors with larger and more prolonged heart rate, blood pressure and neuroendocrine changes. This can contribute to cardiovascular and other diseases. Hostility is also positively associated with inflammatory markers, which could be another psychophysiological mechanism linking hostility to CHD and other negative health outcomes. Hostility is associated with increased exposure to interpersonal stressors and reduced levels of social support. Hostility is associated with a wide variety of negative health behaviours. Social dominance is also associated with increased risk for CHD. Sympathetic activation associated with chronic challenges to social status contributes to the association between individual differences in social behaviour and subsequent cardiovascular disease.

Neuroticism (i.e. negative affect) refers to the tendency to experience distress and the cognitive and behavioural styles that follow from this tendency. It is associated with excessive somatic complaints. This personality trait predicts serious health problems. However, research in this area is often complicated due to measurement problems. There are important differences between individual differences in neuroticism and an emotional disorder. Anxiety and depression are associated with increases in blood pressure and the development of hypertension.         Neuroticism is associated with an increased risk of stroke and death of cardiovascular disease among people with hypertension.

Depression predicts reduced longevity in survivors of a stroke. Neuroticism is associated with reduced survival among patients with end-stage renal disease. Neuroticism is associated with negative health behaviours. Chronic anxiety and depressive symptoms are associated with altered autonomic regulation of the cardiovascular system (1), immune suppression (2) and increased inflammation (3). Chronic negative affect are associated with increased exposure to daily stressors and future life difficulties.

The tendency to hold optimistic expectations (i.e. optimism vs. pessimism) is associated with important health outcomes. Optimism refers to the tendency to expect good experiences in the future. Optimists tend to attribute life difficulties to temporary, specific and external causes. Optimism and pessimism are not opposite poles on a single personality trait but distinct and related dimensions. Optimism is associated with reduced incidence of medical complications. Pessimism is associated with decreased survival among women with breast cancer, although optimism is not related to survival in this case. Hopelessness is associated with the tendency to develop hypertension (1), increased incidence of death from cardiovascular disease and cancer (2), incidence of myocardial infarction (3), greater progression of atherosclerosis (3) and reduced longevity (4). Greater optimism is associated with a greater immune functioning and lower ambulatory blood pressure. It is also associated with more effective participation in health care. It is also associated with greater levels of social support.

Conscientiousness predicts longevity among initially healthy persons and survival among patients with end-stage renal disease. Curiosity is also related to longevity, independent of medical risk and health behaviour. A sense of coherence refers to the extent to which individuals find their lives to be comprehensible, manageable and meaningful. This predicts all-cause mortality, independent of medical risk factors, health behaviours and individual differences in hostility and neuroticism.

The tendency to deny or minimize negative emotions (e.g. repressive coping, denial, expressive suppression) is associated with increased risk of cancer (1), cancer progression (2) and hypertension (3). The health consequences of repressive coping could be due to stress moderation mechanisms. Repressive coping is associated with more stressful social interactions and other interpersonal difficulties.

Low socio-economic status confers risk of serious health problems. It is associated with potentially stressful experiences. Adverse events during childhood are associated with greater risk of CHD. Traditional gender roles renders the genders susceptible to different stressors (e.g. women more susceptible to stressors in communion). Cultural differences may influence the relative importance of personality factors as determinants of health. Consideration of gender, age, culture and ethnicity has the potential to produce a more detailed account of associations between personality and health.