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So is there any research from the basic science of the laboratory bench to explain what’s happening when we take a placebo? Well, here and there, yes, although they’re not easy experiments to do. It’s been shown, for example, that the effects of a real drug in the body can sometimes be induced by the placebo ‘version’, not only in humans, but also in animals. Most drugs for Parkinson’s disease work by increasing dopamine release: patients receiving a placebo treatment for Parkinson’s disease, for example, showed extra dopamine release in the brain.

Zubieta [2005] showed that subjects who are subjected to pain, and then given a placebo, release more endorphins than people who got nothing. (I feel duty bound to mention that I’m a bit dubious about this study, because the people on placebo also endured more painful stimuli, which is another reason why they might have had higher endorphins: consider this a small window into the wonderful world of interpreting uncertain data.)

If we delve further into theoretical work from the animal kingdom, we find that animals’ immune systems can be conditioned to respond to placebos, in exactly the same way that Pavlov’s dog began to salivate in response to the sound of a bell. Researchers have measured immune system changes in dogs using just flavoured sugar water, once that flavoured water has been associated with immunosuppression, by administering it repeatedly alongside cyclophosphamide, a drug that suppresses the immune system.

A similar effect has been demonstrated in humans, when the researchers gave healthy subjects a distinctively flavoured drink at the same time as cyclosporin A (a drug which measurably reduces your immune function). Once the association was set up with sufficient repetition, they found that the flavoured drink on its own could induce modest immune suppression. Researchers have even managed to elicit an association between sherbet and natural killer cell activity.

What does this all mean for you and me?

People have tended to think, rather pejoratively, that if your pain responds to a placebo, that means it’s ‘all in the mind’. From survey data, even doctors and nurses buy into this canard. An article from the Lancet in 1954—another planet in terms of how doctors spoke about patients—states that ‘for some unintelligent or inadequate patients, life is made easier by a bottle of medicine to comfort the ego’.

This is wrong. It’s no good trying to exempt yourself, and pretend that this is about other people, because we all respond to the placebo. Researchers have tried hard in experiments and surveys to characterise ‘placebo responders’, but the results overall come out like a horoscope that could apply to everybody: ‘placebo responders’ have been found to be more extroverted but more neurotic, more well-adjusted but more antagonistic, more socially skilled, more belligerent but more acquiescent, and so on. The placebo responder is everyman. You are a placebo responder. Your body plays tricks on your mind. You cannot be trusted.

How do we draw all this together? Moerman reframes the placebo effect as the ‘meaning response’: ‘the psychological and physiological effects of meaning in the treatment of illness’, and it’s a compelling model. He has also performed one of the most impressive quantitative analyses of the placebo effect, and how it changes with context, again on stomach ulcers. As we’ve said before, this is an excellent disease to study, because ulcers are prevalent and treatable, but most importantly because treatment success can be unambiguously recorded by having a look down there with a gastroscope.

Moerman examined 117 studies of ulcer drugs from between 1975 and 1994, and found, astonishingly, that they interact in a way you would never have expected: culturally, rather than pharmacodynamically. Cimetidine was one of the first ulcer drugs on the market, and it is still in use today: in 1975, when it was new, it eradicated 80 per cent of ulcers, on average, in the various different trials. As time passed, however, the success rate of cimetidine deteriorated to just 50 per cent. Most interestingly, this deterioration seems to have occurred particularly after the introduction of ranitidine, a competing and supposedly superior drug, onto the market five years later. So the self-same drug became less effective with time, as new drugs were brought in.

There are a lot of possible interpretations of this. It’s possible, of course, that it was a function of changing research protocols. But a highly compelling possibility is that the older drugs became less effective after new ones were brought in because of deteriorating medical belief in them. Another study from 2002 looked at seventy-five trials of antidepressants over the previous twenty years, and found that the response to placebo has increased significantly in recent years (as has the response to medication), perhaps as our expectations of those drugs have increased.

Findings like these have important ramifications for our view of the placebo effect, and for all of medicine, since it may be a potent universal force: we must remember, specifically, that the placebo effect—or the ‘meaning effect’—is culturally specific. Brand-name painkillers might be better than blank-box painkillers over here, but if you went and found someone with toothache in 6000 BC, or up the Amazon in 1880, or dropped in on Soviet Russia during the 1970s, where nobody had seen the TV advert with the attractive woman wincing from a pulsing red orb of pain in her forehead, who swallows the painkiller, and then the smooth, reassuring blue suffuses her body … in a world without those cultural preconditions to set up the dominoes, you would expect aspirin to do the same job no matter what box it came out of.

This also has interesting implications for the transferability of alternative therapies. The novelist Jeanette Winterson, for example, has written in The Times trying to raise money for a project to treat AIDS sufferers in Botswana—where a quarter of the population is HIV positive—with homeopathy. We must put aside the irony here of taking homeopathy to a country that has been engaged in a water war with neighbouring Namibia; and we must also let lie the tragedy of Botswana’s devastation by AIDS, which is so phenomenal—I’ll say it again: a quarter of the population are HIV positive—that if it is not addressed rapidly and robustly the entire economically active portion of the population could simply cease to exist, leaving what would be effectively a non-country.

Leaving aside all this tragedy, what’s interesting for our purposes is the idea that you could take your Western, individualistic, patient-empowering, anti-medical-establishment and very culturally specific placebo to a country with so little healthcare infrastructure, and expect it to work all the same. The greatest irony of all is that if homeopathy has any benefits at all for AIDS sufferers in Botswana, it may be through its implicit association with the white-coat Western medicine which so many African countries desperately need.

So if you go off now and chat to an alternative therapist about the contents of this chapter—which I very much hope you will—what will you hear? Will they smile, nod, and agree that their rituals have been carefully and elaborately constructed over many centuries of trial and error to elicit the best placebo response possible? That there are more fascinating mysteries in the true story of the relationship between body and mind than any fanciful notion of quantum energy patterns in a sugar pill?

To me, this is yet another example of a fascinating paradox in the philosophy of alternative therapists: when they claim that their treatments are having a specific and measurable effect on the body, through specific technical mechanisms rather than ritual, they are championing a very old-fashioned and naïve form of biological reductionism, where the mechanics of their interventions, rather than the relationship and the ceremony, have the positive effect on healing. Once again, it’s not just that they have no evidence for their claims about how their treatments work: it’s that their claims are mechanistic, intellectually disappointing, and simply less interesting than the reality.