Chronic pain differs from acute pain. The latter is a normal sensation triggered in the nervous system to alert you to possible injury and the need to take care of yourself. Chronic pain persists. Pain signals keep firing in the nervous system for weeks, months, even years.
There may have been an initial mishap e.g. sprained back or serious infection, or there may be an ongoing cause of pain e.g. arthritis, cancer or ear infection.
Some people on the other hand suffer chronic pain in the absence of any past injury or evidence of body damage. Many chronic pain conditions affect older adults.
Common chronic pain complaints include headache, low back pain, cancer pain, arthritis pain, neurogenic pain (pain resulting from damage to the peripheral nerves or to the central nervous system itself) and psychogenic pain (pain not due to past disease or injury or any visible sign of damage inside or outside the nervous system).
Many people with chronic pain can be helped if they understand all the causes of pain and the many and varied steps that can be taken to undo what chronic pain has done. Scientists believe that advances in neuroscience will lead to more and better treatments for chronic pain in the years to come.
Reviewed by Dr Andrew Rose-Innes, Yale University School of Medicine, 2007