Medical scientists have rid us of scourges ranging from sepsis to smallpox, and have improved the length and quality of our lives in countless ways.
Yet, in clinics from rural Russia to Dubai, doctors have a huge lesson in humility every day. They can do next to nothing for many of their patients suffering from chronic pain.
Internationally, about one in five adults suffers from a source of pain that lasts for years, at an annual cost to the global economy of more than US$1 trillion (Dh3.67 trillion).
Its causes are many, the most common being old injuries, cancer and arthritis.
And for countless millions of those affected, medical science can offer little, if any, relief.
This week, some of the world’s leading experts on chronic pain will meet in Abu Dhabi to brief the region’s physicians on the most recent developments in tackling the problem.
The venue is significant: the UAE has one of the world’s highest rates of chronic pain from spinal problems. Almost two-thirds of the population are affected – more than double the rate in many countries.
The good news is that the problem is being taken more seriously than before, and new research is pointing to methods of tackling chronic pain that go beyond popping pills.
At centre stage is a technique that takes its cure from a time-honoured remedy all parents tell their kids after a fall: rubbing where it hurts tends to make the pain fade.
This may sound like a silly bit of folk wisdom that owes more to simple distraction techniques than hard science. Yet in its implications, it may yet prove as important to medical science as Isaac Newton’s “trivial” observation of a falling apple proved to physicists.
As those at this week’s conference will hear, the effectiveness of rubbing is backed by the best current explanation of pain, which dates back 50 years and is now being incorporated into new pain-killing techniques.
The idea that pain actually needs explaining seems bizarre but the lack of effective relief for chronic pain speaks to the complexity of what seems to be a simple phenomenon.
Most of us probably think of the origins of pain in terms that date back to the Greeks. These were crystallised by the 17th century French philosopher Rene Descartes, who regarded pain as the result of damage to one part of the body being reported directly to the brain by nerves.
Even at the time, it was clear this was overly simplistic. Military physicians were familiar with soldiers carrying on the fight despite being severely injured, only feeling the pain once out of the war zone.
Experiments also revealed how patients with damaged nerves could be left in agony simply by brushing lightly on their skin at just the right rate.
This lack of a simple link between pain perception and the size of an injury or the intensity of the nerve signals remained unexplained until 1965, when two researchers put forward the current leading theory of pain.
In a now celebrated paper in the journal Science, Canadian psychologist Ronald Melzack and British neurologist Patrick Wall outlined the so-called Gate Control Theory, which explains the riddles – including the effectiveness of rubbing the source of pain. As its name suggests, the theory proposes that nerve impulses caused by injury do not simply travel to the brain. Instead, they must pass first through a series of "gates" controlled by various stimuli.
The sheer intensity of the pain signals is, naturally enough, one such stimulus. Crucially, however, it is not the only one. The theory asserts that the brain also plays a role in controlling these neural gates, and thus the strength of pain experienced.
This explains why, for example, pain might not be felt when the brain is otherwise engaged in, say, the fight for survival, or may even be intensified at times of low mood.
The theory also argues that the gates are under the influence of other forms of signal – such as heat, cold and pressure – reducing transmission of the pain signal to the brain. This explains the painkilling effect of ice-packs and hot towels to simple massaging of the affected area.
And as this week’s conference will show, the gate theory has also led to a radically different strategy to combating chronic pain. The best-known is the so-called Transcutaneous Electrical Nerve Stimulation (Tens), where patients wear a device that feeds electric signals into specific nerve groups, thus closing the “gates” and reducing pain.
Tens is cheap, simple and has none of the problems of pain-killers, such as interaction with other drugs and risk of long-term dependency.
But doubts remain about its effectiveness. Although many patients have benefited from it, the outcome of scientific trials remains equivocal.
Bizarrely, despite its potential value in treating so common a condition, relatively few independent scientific studies have so far been conducted into the effectiveness of Tens.
Such studies would take patients with chronic pain and randomly select them either to receive treatment using Tens or a fake device.
By comparing the level of improvement among patients in both groups, it is possible to tell if Tens produces a genuine improvement, or whether any benefit is simply due to the placebo effect – where patients “think” themselves better.
To date, while some clinical studies have suggested real benefit from using the Tens devices, the number of patients involved has been too small to rule out the possibility that it is due to the placebo effect.
Many victims of chronic pain are probably less bothered about exactly why they feel better, just as long as they do. In any case, if the benefit was “all in the mind”, that would be perfectly consistent with the gate theory.
Even so, in the absence of anything more compelling than anecdotal evidence, Tens remains under a cloud.
In the meantime, efforts to turn the gate theory into new forms of pain relief continue, with intriguing results. A recent study by researchers at the UCL Institute of Cognitive Neuroscience in London suggests that touch is better at blocking pain than previously thought, while scientists at Wake Forest Baptist Medical Centre in North Carolina have shown that meditation quells pain more effectively than expected by the placebo effect.
Although promising, the research is still in its infancy, which, given how long chronic pain has blighted the lives of so many, is frankly nothing short of scandalous.
Robert Matthews is visiting professor of science at Aston University, Birmingham