Stress Illness and the Immune System

The Physiology and Psychology of Health and Illness
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■ What do we still need to know?
The Terman Life Cycle Study does not provide final answers about the relationship
between personality and health. However, it has generated some important clues and a
number of intriguing hypotheses to be evaluated in research with more representative
samples of participants. Some of that research has already taken place and tends to confirm Friedman’s findings about conscientiousness (Hampson et al., 2006). Further,
Friedman’s decision to reanalyze a set of data on psychosocial development as a way of
exploring issues in health psychology stands as a fine example of how a creative
researcher can pursue answers to complex questions that are difficult or impossible to
study via controlled experiments.
Our discussion of personality and other factors that can alter the impact of stressors should make it obvious that what is stressful for a given individual is not determined fully and simply by predispositions, coping styles, or situations. (See “In Review:
Stress Responses and Stress Mediators.”) Even more important are interactions between
the person and the situation, the mixture of each individual’s coping resources with the
specific characteristics of the situation encountered.
The Physiology and Psychology of
Health and Illness
䉴 How does stress affect your immune system?
Several studies mentioned so far show that people under stress are more likely than
less-stressed people to develop infectious diseases. Other research shows that they are
also more likely to experience flare-ups of the latent viruses responsible for oral herpes (cold sores) or genital herpes (Cohen & Herbert, 1996). In the following sections
we focus on some of the ways in which these and other illnesses are related to the
impact of stress on the immune system and the cardiovascular system.
LINKAGES
Can stress give you the flu?
(a link to Biology and Behavior)
psychoneuroimmunology The field
that examines the interaction of psychological and physiological processes
affecting the body’s ability to defend
itself against disease.
immune system The body’s first line
of defense against invading substances
and microorganisms.
Stress, Illness, and the Immune System
On March 19, 1878, at a seminar before the Académie de Médecine de Paris, Louis
Pasteur showed his distinguished audience three chickens. One bird had been raised
normally and was healthy. A second bird had been intentionally infected with bacteria
but given no other treatment; it was also healthy. The third chicken that Pasteur presented was dead. It had been infected with the same bacteria as the second bird, but it
had also been physically stressed by being exposed to cold temperatures; as a result, the
bacteria killed it (Kelley, 1985).
Research conducted since Pasteur’s time has greatly expanded our knowledge
about how stressors affect the body’s reaction to disease. Psychoneuroimmunology is the field that examines the interaction of psychological and physiological
processes that strengthen or weaken the body’s ability to defend itself against disease
(Ader, 2001).
The Immune System and Illness The body’s first line of defense against invading substances and microorganisms is the immune system. The immune system is
perhaps as complex as the nervous system, and it contains as many cells as the brain
(Guyton, 1991). Some of these cells are in organs such as the thymus and spleen,