Terminal and non-terminal illnesses can both be causes of chronic pain. Chronic Pain Chronic pain has four mechanisms. Nociception is a neural signal of threatened or damaged tissue, and is the classical pain pathway. Central pain states are thought to be caused by abnormal activity in neurons in the afferent pathway. The mechanism for this is not completely understood, and a person may perceive pain where there is no tissue damage.
Behavioral pain is communicated by a word, grimacing, posturing, and other behavioral signals.
A person suffering from chronic pain may undergo a change in personality becoming irritable and moody. The pain is responsible for this change in a formerly good natured person. Pain is emotionally and physically, draining. These dual effects not only take a toll on the ill person but also on her, family and friends. The person with the pain deals not only with the agonizing pain, but also with the guilt and frustration of not being the person she was before the pain.