'Life force' linked to body's ability to withstand stress
Personality trait may affect inflammation, or vice versa, as we age

Our ability to withstand stress-related, inflammatory diseases may be
associated, not just with our race and sex, but with our personality
as well, according to a study published in the July issue of the
journal Brain, Behavior and Immunity. Especially in aging women, low
levels of the personality trait extraversion may signal that blood
levels of a key inflammatory molecule have crossed over a threshold
linked to a doubling of risk of death within five years.

An emerging area of medical science examines the mind-body connection,
and how personality and stress contribute to disease in the aging
body. Long-term exposure to hormones released by the brains of people
under stress, for instance, takes a toll on organs. Like any injury,
this brings a reaction from the body's immune system, including the
release of immune chemicals that trigger inflammation in an attempt to
begin the healing process. The same process goes too far as part of
diseases from rheumatoid arthritis to Alzheimer's disease to
atherosclerosis, where inflammation contributes to clogged arteries,
heart attacks and strokes.

The current study found that that extroverts, and in particular those
high "dispositional activity" or engagement in life, have dramatically
lower levels of the inflammatory chemical interleukin 6 (IL-6). Swiss
psychiatrist Carl Jung defined extroverts as focused on the world
around them and most happy when active and surrounded by people.
Introverts looked inward and were shy.

The definitions of extraversion and other personality traits were
refined by American psychologist Gordon Allport beginning in the
1930s. He reviewed all adjectives in the dictionary used to describe
personality, and attempted to group them into clusters. Over the next
several decades, researchers statistically analyzed these dictionary
terms and discovered that they tended to cluster into five general
dimensions: extraversion vs. introversion, emotional stability vs.
neuroticism, openness vs. closed-minded, agreeable vs. hostile, and
conscientiousness vs. unreliability. These dimensions, known as the
"Five Factor Model" of personality, served to organize hundreds of
specific traits like "activity" for psychologists, similar to the way
the Periodic Table organizes elements for physicists.

"Our study took the important first step of finding a strong
association between one part of extroversion and a specific, stress-
related, inflammatory chemical," said Benjamin Chapman, Ph.D.,
assistant professor within the Rochester Center for Mind-Body Research
(RCMBR), part of the Department of Psychiatry at the University of
Rochester Medical Center, and lead author of the study. "The next step
is to determine if one causes the other. If we knew the direction and
mechanism of causality, and it were low dispositional activity causing
inflammation, we could design treatments to help high-risk patients
become more engaged in life as a defense against disease."

Some past studies had contended, and the current analysis agreed, that
women and minorities have higher levels of IL-6 than white males on
average. Women may be more vulnerable to stress because of hormonal
differences and minorities because of factors like perceived racism,
but those questions have yet to be fully answered. While these trends
exist, variations within these large groups are so great that further
risk markers are needed to better determine any given patient's actual
risk. The current study looked whether particular personality traits,
including low extraversion, were associated with IL-6 levels in a
sample of 103 urban primary care patients aged 40 and older.

You Must Have Been a Calm Baby

According to landmark studies in the early 1990s, extraversion is a
personality trait with three parts: a tendency toward happy thoughts,
a desire to be around others and "dispositional energy," a sense of
innate vigor or active engagement with life ("I'm bursting with
energy; my life is fast-paced"). Other dimensions of extraversion,
such as sensation-seeking, have also been proposed.

While the first two extrovert qualities were not found to track with
inflammation, the current study found increases in "dispositional
activity" came with statistically significant decreases in IL-6 (p = .
001). P values measure the weight that should be attributed to a
finding, with values less than .05 usually deemed significant.

In the current study, a patient's degree of extroversion was
determined by standard tests, including the NEO Five-Factor Inventory,
an instrument based on the Five Factor Model. The study found that the
difference between the 84th percentile of dispositional activity and
the 16th translated roughly into a 1.29 picogram increase in IL-6 per
milliliter of blood.

Those findings took on meaning when comparisons revealed that, for
both white and minority women, the difference between high and low
dispositional energy was enough to shift IL-6 levels above 3.19 pg/ml,
the threshold established by a large, epidemiological study (Harris et
al., 1999) over which five-year mortality risk was found to double.

"If this aspect of personality drives inflammation, dispositional
energy and engagement with life may confer a survival advantage,"
Chapman said. "But we don't know if low dispositional activity is
causing inflammation, or inflammation is taking its toll on people by
reducing these personality tendencies, so we must be cautious in our
interpretation of this association."

The findings recall an idea described as early as 1911 by French
philosopher Henri Bergson that he called élan vitale or ''life force,"
according to the authors. This aspect of adult personality may be
linked to childhood temperament as well. Some babies are very relaxed,
others active. Activity level may reflect a fundamental, biologically-
based energy reserve, although no one has explained the biochemistry
behind it.

The team gauged the magnitude of IL-6 associations for gender, race/
ethnicity and personality by examining the degree to which each factor
was associated with differences between people in IL-6. Of the
differences in inflammation found in the patient sample in levels of
IL-6, about 9 percent of the difference was due to gender, 6 percent
was due to dispositional activity levels and another 4 percent to race/
ethnicity. That a personality trait may contribute more to IL-6 levels
than race/ethnicity was "a great surprise."

Along with Chapman and Jan Moynihan, Ph.D., director of the RCMBR,
Ayesha Khan, Mary Harper, James Walton, Paul Duberstein, Nancy Talbot
and Jeffrey Lyness assisted in the study.

Doug Stockman and Kevin Fiscella from the departments of Family
Medicine and Community and Preventive Medicine at the Medical Center
made important contributions as well. The work was supported by the
General Clinical Research Center (GCRC) at the Medical Center and by
the National Center for Research Resources, part of the National
Institutes of Health.

While it may difficult for patients to change their nature, part of
the solution may be physical exercise as a therapy. The activity
component of extraversion has been linked with exercise by past
studies, as has daily physical activity with lower IL-6 levels in the
aging. Still, the team is not convinced that exercise represents the
whole answer.

"Beyond physical activity, some people seem to have this innate energy
separate from exercise that makes them intrinsically involved in
life," Chapman said. "It will be fascinating to investigate how we can
increase this disposition toward engagement. Potentially, you might
apply techniques developed to treat depression like 'pleasurable event
scheduling' to patients with low dispositional energy, where you get
people more involved in life by filling their time with things they
enjoy as a therapy."

SOURCE: http://www.eurekalert.org/pub_releases/2009-06/uorm-fl061709.php

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Enjoy life and sex and you will be protected from the AA-driven
chronic inflammatory and degenerative diseases?  Or the power of
religion ...  I would suggest that the extrovertism burns more of the
linoleic acid rich midnight oil.

Taka