A drug licensed for use must demonstrate greater effectiveness than a placebo (a capsule of sugar or an inert substance, perhaps) in clinical trials. That standard does not mean, as is sometimes supposed, “greater effectiveness than nothing.”

Many conditions for which we seek treatment respond—at least for a time—to the simple belief that we are receiving treatment. The placebo effect, as that fact is called, is one of the best-attested effects in medicine.

Perhaps we should not be surprised. After all, what we think is happening to us is very much a part of what is happening to us. If you thought that a gelatin capsule had poisoned you, your response would stem from your thoughts and not from the gelatin.

Despite that, far from being an accepted fact, the placebo effect is seen as, at best, a “pesky thing” and at worst, a “trick,” if not a “fraud.” Perhaps that is due to a drive to reduce medical science to the purely physical (physicalism). Physicalism is described at Stanford Encyclopaedia of Philosophy as

The general idea is that the nature of the actual world (i.e. the universe and everything in it) conforms to a certain condition, the condition of being physical. Of course, physicalists don’t deny that the world might contain many items that at first glance don’t seem physical — items of a biological, or psychological, or moral, or social nature. But they insist nevertheless that at the end of the day such items are either physical or supervene on the physical.

On the physicalist view, the body should provide sensory input to the brain which triggers action that preserves and passes on a genetic program. The mind should not be taking in ideas that generate beliefs that are passed on in the form of relief of the body’s condition, relief that can be verified by fMRI imaging. But that is what happens. The evidence from medicine has not co-operated with a physicalist view.

In 2005, New Scientist listed the placebo effect as Number 1 among 13 things that do not make sense:

[s]ometimes, a whole lot of nothing can be very powerful. Benedetti has since shown that a saline placebo can also reduce tremors and muscle stiffness in people with Parkinson’s disease… The neuron activity decreased at the same time as the symptoms improved: the saline was definitely doing something. Michael Brooks, “13 things that do not make sense” at New Scientist

But by 2015, the popular science publication was speaking, not of discrediting, but of harnessing the placebo effect:

Such claims raise eyebrows among those who champion rational thinking. There is often no physiological mechanism by which these and other alternative therapies could work, and they regularly fail to pass the standard tests for efficacy in medicine. But if someone feels better after their chosen remedy, who are we to say it didn’t work for them? Jessica Hamzelou, “How you can harness the placebo effect” at New Scientist

Who indeed? And why isn’t it rational thinking? Pain relief, however produced, can hardly be less real than the pain. One is reminded here of a proverbial question: “If there is no self, whose arthritis is this?”

And what of New Scientist now, in 2018?

Our minds aren’t passive observers simply observing reality as it is; our minds actually change reality. The reality we experience tomorrow is partly the product of the mindsets we hold today.” That’s what Alia Crum told global movers and shakers at this year’s World Economic Forum in Davos, Switzerland. It may sound like New Age nonsense, but Crum, who heads the Mind & Body lab at Stanford University in California, can back up her claims with hard evidence showing the mysterious influence the mind has over our health and well-being. … David Robson, “How a positive mind really can create a healthier body” at New Scientist

Not only is the mind-body connection not “nonsense,” it isn’t really even news. It’s just unpopular. A recent article in the New York Times Magazine illustrates the efforts underway to “problematize” the placebo effect once again. And that’s a tough slog, considering the weight of the evidence that writer Gary Greenberg, psychotherapist and author of The Book of Woe, introduces:

Tell someone a normal milkshake is a diet beverage, and his gut will respond as if the drink were low fat. Take athletes to the top of the Alps, put them on exercise machines and hook them to an oxygen tank, and they will perform better than when they are breathing room air — even if room air is all that’s in the tank. Wake a patient from surgery and tell him you’ve done an arthroscopic repair, and his knee gets better even if all you did was knock him out and put a couple of incisions in his skin. Give a drug a fancy name, and it works better than if you don’t.

Ah. One must pause here to say that pharmaceutical manufacturers who advertise to directly to patients, as they are allowed to do in the United States, put a great deal of thought into that last point (“a fancy name”) and into unpacking the many lifestyle assumptions it encapsulates. If their campaigns didn’t work, it wouldn’t be for lack of trying. Whatever they may say they believe about the placebo effect, they surely believe in it where the bottom line is concerned.

“You don’t even have to deceive the patients. You can hand a patient with irritable bowel syndrome a sugar pill, identify it as such and tell her that sugar pills are known to be effective when used as placebos, and she will get better, especially if you take the time to deliver that message with warmth and close attention. Depression, back pain, chemotherapy-related malaise, migraine, post-traumatic stress disorder: The list of conditions that respond to placebos — as well as they do to drugs, with some patients — is long and growing.” Gary Greenberg, “What if the Placebo Effect Isn’t a Trick?” at The New York Times Magazine

Yes, that’s one of the more remarkable facts about placebos. They can work even for people who know the pills are, in themselves inert.  From one report,

Conventional medical wisdom has long held that placebo effects depend on patients’ belief they are getting pharmacologically active medication. A paper published in the journal Pain is the first to demonstrate that patients who knowingly took a placebo in conjunction with traditional treatment for lower back pain saw more improvement than those given traditional treatment alone.

A researcher explains,

Taking a pill in the context of a patient-clinician relationship—even if you know it’s a placebo—is a ritual that changes symptoms and probably activates regions of the brain that modulate symptoms.” Beth Israel Deaconess Medical Center, “Knowingly taking placebo pills eases pain, study finds” at ScienceDaily

There’s even a practical side to it. It’s been suggested that dummy pills could reduce the needed dosage of serious medications:

The brain cells of people with Parkinson’s disease can be trained to reliably respond to placebo drugs, Italian neuroscientists report. The training wears off after 24 hours but the effect shows it may be possible to reduce the medication needed to treat Parkinson’s by interspersing real drugs with inert injections or pills, says placebo researcher Fabrizio Benedetti at the University of Turin, Italy, who led the work. … Studies of immune responses and pain, including Wager’s work2, 4, have shown — in small trials — that learned placebo effects can persist even when people know they are being given a fake drug. Benedetti says that although it is not yet clear that this “honest placebo” approach would work for Parkinson’s, it might still be possible to use placebos in clinical practice without deception by informing a patient that inert doses were being interspersed with real medication. Jo Marchant, “Parkinson’s patients trained to respond to placebos” at Nature

If we are not committed to a physicalist perspective, it all makes sense. The pain relief comes from participating in an approved ritual of healing. The relief is subjective, yes, but then so is the pain. Both, clinically measured, are experienced by a subject. Is there any such thing as pain no subject is experiencing?

 One user of Trader Joe’s melatonin tablets, a Digg editor, views his insomnia cure as a placebo. But he concludes, philosophically,

Am I convinced that the melatonin inside them is what changed my life? Absolutely not. At this point, I take them knowing full-well that some combination of Pavlovian or placebo effect is the thing that’s reliably knocking me out. I’m convinced that they work for me, and that’s all that really matters. Steve Rousseau, “The Placebo Effect Is Way More Real Than We Thought, And Other Facts” at Digg

The right ritual, however mundane, works.

The placebo effect may even be getting stronger, at least in the United States. Greenberg tells us, “A 2015 study published in the journal Pain analyzed 84 clinical trials of pain medication conducted between 1990 and 2013 and found that in some cases the efficacy of placebo had grown sharply, narrowing the gap with the drugs’ effect from 27 percent on average to just 9 percent.” One explanation offered is that more direct marketing to American patients heightens their expectations of the medication and/or the medical rituals by which it is administered. That would spike the placebo effect.

Ted Kaptchuk, head of Harvard Medical School’s Program in Placebo Studies and the Therapeutic Encounter, and molecular biologist Kathryn Hall have been working on a “molecules” approach to the placebo effect, on the theory that they can place it squarely within current science that way. As Greenberg explains, they have isolated “a snippet” of the genome called rs4680 that governs the production of an enzyme called COMT, which varies between people and appears to relate to the response to placebo effects. It’s important to know about COMT but one senses that its discovery doesn’t address the cultural discomfort that the placebo effect evokes. Consider some of the objections:

Greenberg tells us that “Without a clear knowledge of how it works, doctors can’t know when to deploy it, or how.” But is that true?

Eastern White Cedar

We can certainly use something without a clear knowledge of how it works. Indigenous North Americans cured a deadly disease, scurvy, by making a tea from the needles and bark of conifers (possibly the Eastern white cedar). The original users probably did not understand “how it works” in terms of biochemistry (the tea replenished the ascorbic acid, vitamin C, missing from winter diets). But they did know how to save their lives for millennia;  later, they saved the Europeans who were settling among them.

The problem with not knowing exactly how a cure works is that we can’t easily extrapolate it to further uses. If you know why the bark tea works, for example, you also know why it won’t help much with infected wounds. But is there any evidence that those who disparage the placebo effect even want to extrapolate it to other uses?

He also notes that the placebo effect is considered to be caused by “expectancy” and Pavlovian “conditioning”: “These theories, which posit that the mind acts upon the body to bring about physical responses, tend to strike doctors and researchers steeped in the scientific tradition as insufficiently scientific to lend credibility to the placebo effect.” But the effect does not suffer from a shortage of credibility as such; it is one of the standards against drugs are measured. Theorists do not like its existence, period. The assignment of psychological terminology like “expectancy” and Pavlovian “conditioning” adds nothing to our knowledge.

Greenberg writes as though he is uncomfortable with the implications of the placebo effect himself (“possibly opening a Pandora’s box for Western medicine”). Or perhaps it is just that he thinks his readers will be. He asks,

After all, if Hall is right that clinician warmth is especially effective with a certain genotype, then, as she wrote in the paper presenting her findings from the I.B.S./sham-acupuncture study, it is also true that a different group will “derive minimum benefit” from “empathic attentions.” Should medical rituals be doled out according to genotype, with warmth and caring withheld in order to clear the way for the drugs? Gary Greenberg, “What if the Placebo Effect Isn’t a Trick?” at The New York Times Magazine

Well, with appropriate consent, why don’t we try it and see? We already know that many high responders know they are receiving placebos—and they’re fine with that. If it’s true that some patients respond better to the “clinical” approach, isn’t that information too? The reality is that the placebo effect will continue to play a role in medicine whether it is explained away or recognized, understood, and employed. But recognizing and working with it has philosophical implications for our understanding of the mind’s relationship to the body that we cannot then just dismiss.

Note: Placebos work best when the problem is pain or discomfort. They are not reputed to fight cancer, for example, though they can reduce the discomfort of the disease’s side effects, alongside other treatments. Side effects can be a significant quality-of-life issue in themselves.

See also: Researchers find loneliness is hard on the brain. What we think about our lives really does affect our health. What’s less often recognized is that loneliness could cause be a cause of brain damage as well, at least if we go by rodent studies.

and

Panpsychism: You are conscious but so is your coffee mug? Materialists have a solution to the problem of consciousness, and it may startle you