Patients seeking care for pain want to know whether it is likely to improve or run a chronic course, not just its cause and how it might be relieved and managed. But it is difficult for the doctor to give a clear and reassuring answer. Korff and Dunn, in their book, Chronic Pain Reconsidered, explain: “Physicians’ abilities to provide guidance regarding pain’s likely course, as well as clinical and epidemiologic research, are hampered by lack of clear-cut, evidence-based operational criteria for classifying chronic pain.”( 2008, 267-276)
How chronic pain is initiated, maintained and prolonged is the crucial question in the field of pain research. Apparently, there is not always a direct association between tissue damage, pain perception and behavior. While acute pain has a clear and understandable biological function and keeps one out of harm’s way, as seen with the reflex reaction to putting one’s hand on the hot stove, chronic pain without any recognizable tissue injury does not appear to serve any purpose for the individual.
The International Association for the Study of Pain defines chronic pain: ‘‘pain which persists past the normal time of healing . . . With non-malignant pain, three months is the most convenient point of division between acute and chronic pain, but for research purposes, six months will often be preferred” (Van Korff & Dunn, 2008).
Defining chronic pain solely by duration is based on the view that acute pain signals potential tissue damage, whereas chronic pain results from central and peripheral sensitization, in which pain is sustained after nociceptive inputs have diminished.
We’ll explore these ideas further in the next post.