What does research tell us about the origins of
complex, unexplained modern illnesses?
BY TORI DEANGELIS
Medically unexplained illnesses provide a unique forum to examine mind-body factors and how culture and gender can influence symptoms,
psychologists and others say.
irritable bowel syndrome, while a person with a pain history
might develop fibromyalgia.
In addition, Johnson says, people who have these conditions
often aren’t receptive to psychological explanations. “There is a
lot of pressure to find a medical explanation and treatment. Yet
I’ve been in this field for 20 years and it doesn’t seem like we’ve
gotten very far in discovering causes,” she says.
One promising theory is the multifactorial “central
sensitivity hypothesis,” which posits that as a result of early
trauma such as childhood abuse, childhood illness or a
childhood accident, some people are highly sensitive to sensory
stimuli and have a low tolerance for pain. In turn, “that sets up a
dysregulation of your stress system, so you feel symptoms more
intensely,” Johnson says.
That theory was underscored by research unveiled at the
American College of Rheumatology’s annual meeting in
November by medical researcher Richard Harris, PhD, of the
University of Michigan, who presented imaging studies showing
that people with fibromyalgia have a down-regulation in opioid
receptor activity that may exaggerate their sensitivity to pain.
Other researchers are seeking strictly biological explanations
for some of these debilitating disorders. Among them is DePaul
University psychologist Leonard Jason, PhD, who discovered
during 10 years of epidemiological research that chronic fatigue
syndrome was more likely to afflict low-income minorities