A recent article by the USNews Health section of their website had some very useful information about the nature of chronic pain and the current medical knowledge about the disease. The original article, written on 9/5/2012 by Michelle Andrews, may be found by clicking here.
About one third of Americans, an estimated 100 million people, suffer
from chronic pain, making it one of the most common reasons people
visit the doctor. Pain can be the side effect of serious medical
problems like cancer and rheumatoid arthritis, but it also exists
independently of any other medical condition. Despite decades of
research and millions of dollars devoted to studying the problem,
current therapies provide only marginal relief for many sufferers. But
there are glimmers of hope. Among other developments, researchers today
are working on novel approaches that focus on controlling activity in
the brain's pain centers and on cells previously thought to play only a
supporting role in the central nervous system.
Success can't come any too soon. Prescription drugs like Oxycontin,
Percocet, and Vicodin, while effective weapons against chronic pain,
are under increasing scrutiny because they can be addictive for
patients and have also been abused by others who simply take them,
without prescriptions, for their euphoria-producing effects. To relieve
the widespread overdependence on painkillers, researchers are
investigating new ways to attack this most primitive sensation and not
merely mask it, as opioid drugs do. But researchers have to tread
carefully, as pain can help keep "us out of trouble," as in a warning
to draw back from a hot stove, says Sean Mackey, chief of the pain
management division at Stanford University School of Medicine. The goal
is to lessen or eliminate chronic pain that serves no useful purpose.
Often, pain starts with a physical injury such as a burn or scrape.
When tissue is damaged, sensory receptors in the skin or elsewhere in
the body send signals in the form of electrical impulses along nerves,
or neurons, to the spinal cord. In the spinal cord, chemical
neurotransmitters are released that activate other nerves, sending an
electrical signal to the brain, where it is processed and interpreted as
Until recently, researchers have focused on the nerves at the site
where the pain occurs, like an aching knee joint, and on the spinal
cord. But pain is dependent on perception, which occurs in the brain.
The sensation is a complex bodily experience incorporating the physical
feeling ("That hurts!"), the emotional reaction ("Why did I grab the
hot pan?"), and the intellectual response ("I need to be more
careful.") "Without perception there is no pain," notes Kenneth
Follett, professor and chief of neurosurgery at the University of
Nebraska Medical Center. Some soldiers wounded in battle, for example,
have said they didn't know they were hurt until after the danger had
passed. The reasons for this are unclear, says Follett, but attention
likely plays a role. When it is focused elsewhere, the brain may not
At the Stanford Systems Neuroscience & Pain Laboratory, Mackey
is trying to better understand the mechanisms involved. In one study,
he and colleagues performed brain scans on subjects' anterior cingulate
cortices, one of the areas responsible for perceiving and controlling
pain. The subjects, whose hands were intermittently heated by a probe,
could watch on a screen as their brain activity increased or decreased,
depending on the intensity of the pain they were feeling. Researchers
suggested ways subjects could control the sensation, such as by
focusing on something else or attempting to change their perception of
the pain from something frightening and damaging to something neutral.
After four 13-minute sessions, healthy subjects, who were included in
the study, reduced their sensation of pain by 23 percent. Chronic pain
patients, who learned to control their body's own pain sensations,
reported an even more dramatic average reduction of 64 percent.
"We thought, maybe we can help people control their own brain
activity," Mackey explains. He says researchers hope that, with
increased training, patients can "reshape" the circuits responsible for
pain. Mackey and his colleagues were recently awarded a $9 million
grant from the National Center for Complementary and Alternative
Medicine, part of the National Institutes of Health, to study the
effectiveness of this neurofeedback technique and other mind-body
approaches to treating chronic low back pain.