Individuals may vary in how well they can protect themselves from illness, depending on personality traits as well as on physiological differences, suggest the results of a preliminary study.
Anna L. Marsland, PhD, RN, of the Behavioral Medicine Program at the Western Psychiatric Institute and Clinic at the University of Pittsburgh School of Medicine, in Pennsylvania, and colleagues tested how 84 study participants responded to a vaccine for the viral infection known as hepatitis B. This vaccination prompts the immune system to mount a defense 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 negative affect, or neuroticism. Individuals with high scores on tests of negative affect tend to be moody, nervous and easily stressed.
Those study participants with higher scores on the neuroticism test also tended to have lower immune system responses to the hepatitis vaccine, Marsland and colleagues found.
The study findings are published in the January issue of the journal Health Psychology.
Previous studies have found that individuals with high scores for neuroticism tended to report more disease symptoms.
Marsland and colleagues also asked the study participants to give a short videotaped speech in order to measure their physiological responses to a stressful event. In accordance with the findings of other studies that stress can affect the immune system, the immune function of the study participants were reduced somewhat as a result of the speech — with those who had a lower immune response to the vaccination showing the most reduction, the researchers found.
Those individuals who had a lower immune response to the vaccination may be more vulnerable to the effects of stress or to the effects of a personality trait like neuroticism and therefore may be more vulnerable to disease. “This study provides initial evidence that individual differences in the magnitude of stress-induced reduction of immune function may be of clinical significance,” said Marsland.