Originally published 2016-01-03.
Yes, personality and health are linked, but the links are modest and work mostly through everyday habits. Across many large studies, the clearest signal comes from conscientiousness: organised, self-disciplined people tend to develop fewer chronic diseases and live somewhat longer. A tendency towards anxiety and negative mood (neuroticism) is associated with more health problems, especially mental-health conditions.
Two studies published in 2015 helped bring this topic to a wide audience. One, from the University of Nottingham and the University of California, Los Angeles (UCLA), looked at how personality relates to the activity of immune genes. The other, from Washington University in St. Louis, tracked which older adults went on to be diagnosed with common diseases. Here is what each found, how the five main personality traits compare, and what the research does and does not mean for you.
The five traits researchers measure
Most modern research uses the Big Five model, which describes personality along five broad dimensions. Each is a spectrum, and everyone sits somewhere along all five.
- Conscientiousness: self-discipline, reliability, planning and impulse control.
- Openness to experience: curiosity, imagination and interest in new ideas and art.
- Extraversion: energy, sociability and assertiveness, as opposed to a quieter, more reserved style.
- Agreeableness: kindness, trust, cooperation and concern for getting along with others.
- Neuroticism: a tendency to experience strong negative emotions such as worry, anger or sadness.
Twin studies suggest that roughly 40 to 60 percent of the differences between people on each trait are linked to genes, with the rest shaped by environment and experience. Traits also shift gradually over a lifetime; most people become somewhat more conscientious and agreeable, and less neurotic, as they age.
The Nottingham–UCLA immune gene study
Health psychologists led by Professor Kavita Vedhara at the University of Nottingham worked with UCLA's Social Genomics Core Laboratory to test whether personality is reflected in the immune system. They recruited 121 healthy adults (86 women and 35 men, average age 24) who completed a standard Big Five questionnaire, the NEO-FFI, and gave blood samples.
Using microarray technology, the team measured the activity of two groups of genes in white blood cells: genes involved in inflammation, and genes involved in antiviral defence and antibody production. They also recorded smoking, drinking and exercise so these habits could be taken into account.
The results were narrower than some headlines suggested:
- Higher extraversion went with greater activity of pro-inflammatory genes.
- Higher conscientiousness went with lower activity of those genes.
- Openness showed a weak trend towards lower inflammatory activity.
- Neuroticism and agreeableness showed no link, and no trait was linked to the antiviral and antibody genes.
Vedhara suggested a possible explanation: sociable people may meet more germs, so an immune system primed for inflammation could be useful for them. She was careful about which comes first, asking: Is this our biology determining our psychology or our psychology determining our biology?
With 121 mostly young volunteers and a single blood sample each, the study shows an association, not a cause.
Notably, it found no support for the old idea of a "disease-prone personality", in which negative emotions alone make people ill.
The Washington University disease study
A separate study, led by psychologist Joshua Jackson with colleagues Stephen Weston and Patrick Hill, followed several thousand older Americans taking part in the long-running Health and Retirement Study. Participants rated their personality on a 1–4 scale, and the researchers tracked which people were newly diagnosed with common diseases over the following years.
Each one-point increase on a trait was linked to these changes in the odds of a new diagnosis, as reported at the time:
- Conscientiousness: about 37 percent lower odds of stroke, 27 percent lower for high blood pressure, 23 percent lower for arthritis and 20 percent lower for diabetes.
- Openness: about 31 percent lower odds of stroke, 29 percent lower for high blood pressure, 21 percent lower for arthritis and 17 percent lower for heart conditions.
- Extraversion: about 26 percent lower odds of high blood pressure only.
- Agreeableness: about 21 percent lower odds of arthritis.
- Neuroticism: higher odds of several conditions, roughly 24 percent for heart conditions, 29 percent for lung disease, 37 percent for high blood pressure and 25 percent for arthritis.
The study did not separate type 1 and type 2 diabetes, though Jackson noted that new diagnoses in older adults would mostly be type 2, the form linked to weight and lifestyle. He also said the agreeableness result was new and should be repeated before anyone relies on it.
Why personality might affect health
Researchers point to several overlapping pathways rather than one hidden mechanism:
- Habits. Conscientious people are more likely to eat well, exercise, avoid smoking, take medicines as prescribed and keep medical appointments. Across studies, conscientiousness is the strongest personality predictor of a longer life.
- Stress. High neuroticism means more frequent and intense stress responses, which may affect blood pressure, sleep and inflammation over time. It is also strongly linked with anxiety and depression.
- Relationships. Warm, agreeable people often have stronger social ties, and good social connection is consistently associated with better health.
- Flexibility. Open people may find more varied ways to cope with stress and may communicate more readily with doctors, though this is less well studied.
The link can also run the other way. Illness, pain and the early stages of conditions such as dementia can change how people behave and feel, which in turn changes how they score on personality tests.
Common myths about personality and illness
"Worriers make themselves sick." Neuroticism is associated with higher risk of some conditions, but the effect is modest and partly explained by habits and stress. Nobody causes their own illness by having an anxious temperament.
"Type D personality is a proven heart risk." Dutch psychologist Johan Denollet described Type D, combining negative mood with social inhibition, in the 1990s. Early small studies linked it to worse outcomes after heart attacks, but larger later studies did not confirm a higher risk of death, though a 2023 pooled analysis did find a link with other adverse events.
"Each emotion damages a specific organ." Traditional Chinese Medicine pairs emotions with organs: anger with the liver, worry with the spleen, grief with the lungs, fear with the kidneys and joy with the heart. These ideas are part of a historical philosophy and have not been supported by scientific evidence. Neither of the studies above tested them.
What you can take from this research
Personality is a tendency, not a destiny. The effects found in these studies are averages across large groups and cannot predict any one person's health. A highly conscientious person can still fall ill, and a disorganised one can live a long, healthy life.
The encouraging message is that the behaviours behind the links can be learned. Keeping a routine, planning meals, setting reminders for medication and check-ups, staying active and keeping in touch with friends all bring some of the benefits associated with conscientious and sociable people, whatever your natural temperament.
If worry, low mood or stress are affecting your daily life or sleep, talk to a doctor. Effective help exists, and dealing with these feelings early is good for both mental and physical health.
Sources: Vedhara K. et al. (2015), Personality and gene expression, Brain, Behavior, and Immunity; Weston S.J., Hill P.L. and Jackson J.J. (2015), Personality traits predict the onset of disease, Social Psychological and Personality Science; Wikipedia: Big Five personality traits; Wikipedia: Type D personality; original summary by April McCarthy, Prevent Disease.
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