Pain - a compassionate science

Pain is essential, but we avoid it as much as we can. Without pain we would die from injuries and diseases we failed to notice. Pain is familiar, but we understand little about it; it is the most common reason why patients visit doctors, but few of them have had much training in the subject. After four years in medical school "the fully qualified doctor usually emerges with only three to fours hours of tuition on pain." That last comment is a quote from the book and demonstrates Professor Wall's insight into the predicament of chronic pain sufferers. He understands because he is an acknowledged world expert on the subject. He understands deeply because he has cancer.

Patrick Wall comes to his subject from a background in clinical practice, academic research and scientific study. He was joint proposer of the "gate" theory of pain and joint inventor of the TENS machine (See Note 1). He is a thoughtful and sympathetic man whose concern for patients comes through in this most readable of medical books. It is a popularising book, but it is high time someone popularised this neglected subject.

The classic understanding of pain is that pain fibres in the nerves connect to a pain tract in the spinal chord, which communicates with the pain centre in the brain (presumed to be the thalamus). This brief outline is still taught to trainee doctors, but Patrick Wall's book dismisses it as a "hundred year old myth". Pain is far more complex, and understanding it requires an open mind and a sympathetic attitude. Pain does not behave in predictable and consistent patterns that can be reduced to simple formulae. Nor does it respond identically to similar treatments in different patients. It is affected by the patient's mind - though that does not mean it is "in the mind" in the sense that some arrogant physicians occasionally hint to distraught sufferers.

As a striking example of the mind's effect on the experience of pain, the book shows a photo of President Ronald Reagan seconds after he had been shot in the chest (1981). In the emergency of the attempted assassination, Reagan's unconscious mind gave priority to escape and his face displays alertness rather than agony. Not until he was safely on his way to hospital did the President report the pain, which proved that a bullet had entered his body. This mental feat is not exclusive to humans, as is demonstrated by another picture showing a racehorse winning the 1980 Epsom Derby 150 yards after he broke a leg. Pain is a necessary response to illness or injury, but it is neither simple nor automatic. The body's control systems, whether human or animal, are able to edit internal nerve messages to suit the over-riding demands of survival. Complex over-ride systems of this kind may well be implicated in the unpredictability of pain.

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