Personality influences immune system
BBC News Online
20 January, 2001
An individual's personality type may play a crucial role in how well they can combat disease and infection, say researchers.
A study has found that personality type may influence the response of the immune system.
Researchers at the University of Pittsburgh School of Medicine tested how 84 volunteers responded to a vaccine for the viral infection hepatitis B.
The vaccination stimulates the immune system into action by introducing a tiny amount of the infectious agent into the body.
The study participants were also given a test to measure a personality trait called neuroticism, or negative affect.
Highly neurotic individuals tend to be moody, nervous and easily stressed.
The researchers found that volunteers who scored highly for neuroticism tended to have a lower immune system response to the vaccine.
The finding may explain why previous research has found that highly neurotic people tend to suffer more symptoms of disease.
Lead researcher Dr Anna Marsland said: "The findings support a link between trait negative affect and an objective health measure - antibody response to vaccination - raising the possibility that individuals high in neuroticism may have less protective immune responses."
The researchers also asked the volunteers to give a short videotaped speech in order to measure their physiological responses to a stressful event.
They found that the stress induced by the speech lowered immune response - most significantly in those people who rated highly for neuroticism.
The researchers say their work suggests neurotic people are more vulnerable to the effects of stress and to disease.
A recent study from Ohio State University found that the effectiveness of a vaccine for pneumonia was reduced if the recipient was suffering from stress.
Dr Kavita Vedhara, of the Medical Research Council Health Services Research Collaboration unit at Bristol University, has conducted research into the link between stress and increased vulnerability to disease in the elderly.
She told BBC News Online: "A relationship between psychological factors and immune outcome is a very, very plausible hypothesis."
Dr Vedhara said there were two possible mechanisms by which psychological factors might influence the immune system.
Firstly, stress and anxiety had a direct impact on levels of hormones such as cortisol which are known to effect immune function.
Secondly, stress can bring about behavioural changes - for instance increased alcohol consumption - which can also impact on the immune system.
The new research is published in the journal Health Psychology.