When pain becomes chronic, it takes on a life of its own in the body and needs special treatment.
Acute pain comes on quickly, often following an injury or infection. And it usually goes away quickly with painkillers or antibiotics. Chronic pain persists. For some people it can occur out of the blue, with no evident triggering injury or illness. It can be experienced as headaches, back pain
, joint pain
, nerve pain, or a myriad of other localized conditions. And it's much more common than many realize: One 2004 study estimated that approximately one-third of Americans had experienced chronic pain in the past year.
Scientists now believe that one cause of chronic pain is a dysfunction of the nervous system. Neurons (cells in the nervous system that communicate with each other) become overexcited and keep firing, even after the original cause (injury or illness, in some cases) has long since passed. The person receives persistent pain signals.
At the same time, scientists believe that the cells that normally inhibit these neurons from firing either die off, begin to degenerate, or are overpowered and become less effective.
"These very excitable neurons don't have the intrinsic mechanism to keep them under control," explains Robert Yezierski, PhD, director of the Comprehensive Center for Pain Research at the University of Florida, in Gainesville, "so wham
, they just start firing out of control."