The second theory for explaining the power of acupuncture is based on the existence of chemicals called opioids, which act as powerful, natural painkillers. The most important opioids are known as endorphins. Some studies have indeed shown that acupuncture somehow stimulates the release of these chemicals in the brain. Not surprisingly, acupuncturists have welcomed these studies, but again there have been sceptics. They question whether acupuncture can release enough opioids to create any significant pain relief, and they cite other studies that fail to confirm any connection between endorphins and acupuncture.
In short, here were two theories that could potentially explain the powers of acupuncture, but as yet they were both too tentative to convince the medical establishment. So instead of accepting either theory, scientists urged further research. Meanwhile, they also began to propose a separate explanation to account for the pain relief provided by acupuncture. In fact, if correct, this third theory could potentially explain all its supposed benefits, not just pain relief. Unfortunately for acupuncturists, this third theory attributed the impacts of acupuncture to the placebo effect, a medical phenomenon with a long and controversial history.
In one sense, any form of treatment that relies heavily on the placebo effect is fraudulent. Indeed, many bogus therapies from the nineteenth century had turned out to be nothing more than placebo‑based treatments. In the next section we will explore the placebo effect in detail and see how it might relate to acupuncture. If the placebo effect can successfully explain the apparent benefits of acupuncture, then 2,000 years of Chinese medical expertise would evaporate. If not, then the medical establishment would be forced to take acupuncture seriously.
The power of placebo
The first medical patent issued under the Constitution of the United States was awarded in 1796 to a physician named Elisha Perkins, who had invented a pair of metal rods which he claimed could extract pains from patients. These tractors, as he dubbed them, were not inserted into the patient, but were merely brushed over the painful area for several minutes, during which time they would ‘draw off the noxious electrical fluid that lay at the root of suffering’. Luigi Galvani had recently shown that the nerves of living organisms responded to ‘animal electricity’, so Perkins’ tractors were part of a growing fad for healthcare based on the principles of electricity.
As well as providing electrotherapeutic cures for all sorts of pains, Perkins claimed that his tractors could also deal with rheumatism, gout, numbness and muscle weakness. He soon boasted of 5,000 satisfied patients and his reputation was buoyed by the support of several medical schools and high‑profile figures such as George Washington, who had himself invested in a pair of tractors. The idea was then exported to Europe when Perkins’ son, Benjamin, emigrated to London, where he published The Influence of Metallic Tractors on the Human Body. Both father and son made fortunes from their devices–as well as charging their own patients high fees for tractor therapy sessions, they also sold tractors to other physicians for the cost of 5 guineas each. They claimed that the tractors were so expensive because they were made of an exotic metal alloy, and this alloy was supposedly crucial to their healing ability.
However, John Haygarth, a retired British physician, became suspicious about the miraculous powers of the tractors. He lived in Bath, then a popular health resort for the aristocracy, and he was continually hearing about cures attributed to Perkins’ tractors, which were all the rage. He accepted that patients treated with Perkins’ tractors were indeed feeling better, but he speculated that the devices were essentially fake and that their impact was on the mind, not the body. In other words, credulous patients might be merely convincing themselves that they felt better, because they had faith in the much‑hyped and expensive Perkins’ tractors. In order to test his theory he made a suggestion in a letter to a colleague:
Let their merit be impartially investigated, in order to support their fame, if it be well‑founded, or to correct the public opinion, if merely formed upon delusion…Prepare a pair of false Tractors, exactly to resemble the true Tractors. Let the secret be kept inviolable, not only from the patient but also from any other person. Let the efficacy of both be impartially tried and the reports of the effects produced by the true and false Tractors be fully given in the words of the patients.
Haygarth was suggesting that patients be treated with tractors made from Perkins’ special alloy and with fake tractors made of ordinary materials to see if there was any difference in outcome. The results of the trial, which was conducted in 1799 at Bath’s Mineral Water Hospital and Bristol Infirmary, were exactly as Haygarth had suspected–patients reported precisely the same benefits whether they were being treated with real or fake tractors. Some of the fake, yet effective, tractors were made of bone, slate and even painted tobacco pipes. None of these materials could conduct electricity, so the entire basis of Perkins’ tractors was undermined. Instead Haygarth proposed a new explanation for their apparent effectiveness, namely that ‘powerful influences upon diseases is produced by mere imagination’.
Haygarth argued that if a doctor could persuade a patient that a treatment would work, then this persuasion alone could cause an improvement in the patient’s condition–or it could at least convince the patient that there had been such an improvement. In one particular case, Haygarth used tractors to treat a woman with a locked elbow joint. Afterwards she claimed that her mobility had increased. In fact, close observation showed that the elbow was still locked and that the lady was compensating by increasing the twisting of her shoulder and wrist. In 1800 Haygarth published Of the Imagination as a Cause and as a Cure of Disorders of the Body, in which he argued that Perkins’ tractors were no more than quackery and that any benefit to the patient was psychological–medicine had started its investigation into what we today would call the placebo effect.
The word placebo is Latin for ‘I will please’, and it was used by writers such as Chaucer to describe insincere expressions that nevertheless can be consoling: ‘Flatterers are the devil’s chaplains that continually sing placebo.’ It was not until 1832 that placebo took on its specific medical meaning, namely an insincere or ineffective treatment that can nevertheless be consoling.
Importantly, Haygarth realized that the placebo effect is not restricted to entirely fake treatments, and he argued that it also has a role to play in the impact of genuine medicines. For example, although a patient will derive benefit from taking aspirin largely due to the pill’s biochemical effects, there can also be an added bonus benefit due to the placebo effect, which is a result of the patient’s confidence in the aspirin itself or confidence in the physician who prescribes it. In other words, a genuine medicine offers a benefit that is largely due to the medicine itself and partly due to the placebo effect, whereas a fake medicine offers a benefit that is entirely due to the placebo effect.