Doctors define chronic pain as pain that persists for more than three months. Some authors prefer to talk about six months. But in general it can be said that chronic pain is that which persists beyond the expected time for healing or recovery.
In opposition, acute pain is that which occurs in a short period of time, and has the usefulness of informing us that something potentially harmful is happening in our body. For example, we speak of acute pain when faced with a toothache, or nephritic colic or the pain of a fracture.
Chronic pain, on the other hand, does not serve as a warning, and is therefore unnecessary for the body. Most of the time, if it persists long enough, it generates major problems, such as depression, anxiety, sleep disturbance, decreased ability to work or to perform usual tasks, impairment of social activities and leisure activities. Very often it also affects the family members of the person suffering from chronic pain.
It is now fully accepted that chronic pain is a disease in itself.