Personality linked to immunity.

Personality linked to immunity

In the last several years, an increasing number of reports have linked particular psychological states, such as depression, to immunological changes that can contribute to ill health (SN: 6/2/84, p. 341). There is now evidence that an individual's overall personality is related to immune function and vulnerability to disease.

J. Stephen Heisel of Charles River Hospital in Wellesley, Mass., and his colleagues compared natural killer (NK) cell activity with scores on the MMPI -- a 566-item personaility inventory with 12 "psychopathology" scales -- obtained from 111 healthy college students. Moderate but statistically significant correlations were found between a laboratory measure of NK cell activity and 10 of the 12 MMPI scales. Students with the highest NK cell activity, they found, has a "healthier" MMPI profile than those with the lowest immune activity.

NK cell activity was not substantially affected by the regular use of medications, alcohol or marijuana; it also did not differ significantly for students who had received medical treatment in the previous year.

There is strong evidence that the NK cell, one of many important elements in the immune system, plays a key regulatory role in protecting against malignancy and infection, the researchers note in the November AMERICAN JOURNAL OF PSYCHIATRY.

While correlations between depression scores and NK cell activity were expected, the investigators point to similarity strong associations -- both negative and positive -- across a wide range of personality scales. For example, high scores on the MMPI depression scale, which imply unhappiness, social withdrawal, guilt, fatigue, low self-esteem and pessimism, are associated with low immune scores, but the link is about as strong as that between the other nine personality scales and NK cell activity.

The strongest association was between lowered immune activity and high scores on the MMPI's maladjustment scale, which is concerned with an individual's "fit" or adaptation to his or her environment. Conversely, high scores on the ego strength scale, often used as an index of general psychological health, coincided with more robust NK cell activity.

Although scores on the hysteria scale, which measures denial of anxiety and depression and conversion of emotional problems into physical symptoms, showed the lowest correlation with the measure of immune function, the six subjects with markedly elevated hysteria scores had very low NK cell activity, according to the researchers.

The findings support theories of an interaction between mental state and immune function, they conclude, but the underlying nature of the interaction remains largely unexplored. Some scientists, for instance, argue that depressed people tend to find depressed mates and transfer genes for psychopathology and low immunity to their descendants; others contend that phobias and social avoidance may be evolutionary adaptations for individuals with lowered immune function.