Podcast | Should GPs prescribe placebos?

Mrs Jones likes blue pills; they work better than those pink ones – even though they are the same drug. But she wouldn’t touch blue mashed potato.

Wine buffs rate a wine higher if they believe it is expensive. Consumers are sure that a brand name product is superior to an identical generic, whether it be atenolol or cornflakes. The kids won’t eat burned sausages at home but round a campfire they taste wonderful. Turn on a red light, and your blood pressure and heart rate will increase.
We know we are influenced by experience, by context, by sensory input, by our expectations, but most of us don’t realise how open to manipulation our judgments are.
Take food. There is an art to creating expectations of food. And a science too. Oxford psychologist Charles Spence’s field is gastrophysics. All our senses are involved in our appreciation of food and drink – not surprising since without them we would not survive. So Spence is investigating how our experience is shaped by our sensory input.

A £275 ‘ticket’ (plus drinks and service) buys you ‘A Journey’ that a celebrity chef has contrived in a laboratory in conjunction with Professor Spence and transferred to his restaurant. There’s no shortage of customers.

Spence’s research also guides multinational food producers. A reassuring crunch as you open the packet makes even stale crisps taste good. Soft drinks and pre-prepared meals, and their packaging, are designed to appeal to the purchaser’s senses before the product reaches their palate. And who wouldn’t be grateful that insights from gastrophysics about the effect of altitude and engine rumble on taste have led airlines to serve more enjoyable food.

In a world that faces food insecurity, overcoming cultural yuck factors could be literally vital. We all like crunchy food, and insects are an underexploited source of nutrition. It’s a matter of presentation.

Gastrophysics has lessons for health care. After 70, our sense of smell deteriorates. Odour contributes far more to taste than our taste buds, so food needs more flavour. Increasing the contribution of the other senses can make a huge difference to how much a frail, elderly and perhaps demented person eats.

Cue mealtimes and boost the appetite by wafting the aroma of a favourite meal from a plug-in. Consider the lighting. Play sounds that have positive associations with food. Mozart for some, Meatloaf for others. Make the food more appetising by replacing soft grey glop on a white plate with coloured food or contrasting coloured crockery. Add crunch, aurally if her teeth aren’t up to toast. Chat with her over her meal. And in hospitals, colour-coded trays for different diets may help staff get the right meal to the right patient, but research shows that if the tray is red, less of the food gets eaten.

There’s something disturbing about how our ‘objective’ responses can be manipulated. It’s a subject of ethical debate, and our views depend on whether we know it is happening. And on whose behaviour is being manipulated. Doctors, who aren’t big consumers of fizzy drinks, generally support measures to reduce their consumption. After all, people need to be protected from themselves. The libertarian right disagrees, and orchestrates public outrage against ‘nanny state’. So governments study behavioural economics and look at nudging, priming – changing subconscious cues – and other non-coercive influences on our behaviour. It has been demonstrated that customers don’t notice when the sugar or salt content of products is reduced gradually. Health by stealth works.

Increasing the contribution of the other senses can make a huge difference to how much a frail, elderly and perhaps demented person eats.

Some of the strategies which could arise from gastrophysics research suggest that it might be possible to massage our senses to the degree that we don’t actually have to eat anything at all to feel well-fed. Already chefs produce food for Instagram rather than nutrition.

Could food become a placebo? Sounds unlikely. But we are learning a lot about placebos, and as with food our responses are summations of complex inputs to our brains. Mild hypertension and ADHD respond nearly as well to placebos as to active drugs. Sham acupuncture improves arm pain. Oxford orthopaedic surgeon Andy Carr is testing the hypothesis that many elective procedures – not just in his own discipline – are no better than placebo. Homeopaths get high ratings from patients. A study determined that two sugar pills are more effective than one.

Functional imaging shows that placebos and active drugs stimulate the same neurological pathways: patients with Parkinson’s disease given placebo treatments release more dopamine, placebo pain relievers activate the same areas of the brain as analgesic drugs and can be blocked by the same compounds. The brain areas which light up when a patient experiences side-effects to real drugs are illuminated by placebos’ dark cousins, nocebo effects.

All arms of a double-blind RCT will give the participants the same care, so placebos are not just effective because the doctor is a better listener. When trials are unblinded, some patients ask to stay on the placebo. And in open-label placebo trials – where patients know they are receiving a placebo – patients still find that the placebo works.
A study of 252 trials of antidepressants showed an impressive NNT of 1 in 3 for one drug only – placebo.

Placebos won’t cure cancer or heal a fracture, but given their demonstrated benefits for patients, and indirectly for doctors and the NHS, should we not be making the most of them?

Nothing destroys the doctor-patient relationship faster than deception, so patients have to know what they are getting. GPs are good at the caring aspects of the consultation, but doctors have little expertise in offering a placebo. One suggestion is “We don't know how it works but we know that some people are helped by this (sugar) pill”. The same could be said of many drugs in the BNF. But we need to be confident that the evidence is firm, the GMC is supportive, the law understanding, and that a critical mass of our colleagues have learned the best way to use these powerful agents in our armamentarium.

It’s an ethical conundrum. But we should accept that our neurological wiring means that total objectivity does not exist. Placebos could be more helpful and less risky than many of the expensive medications we prescribe or procedures we do.
PS If you fancy a whisky and have only a plastic mug to drink out of, don’t broach your best single malt. It will ruin the experience. But you didn’t need Professor Spence to tell you that.

Gastrophysics: The New Science of Eating Charles Spence, 2017 Viking · ISBN-13: 978-0241270080

Judith Harvey

Judith Harvey was a research scientist, ran the VSO programme in Papua New Guinea and taught in a Liverpool comprehensive school before going to medical school. She has been a partner, a salaried GP and a locum, an LMC chair and a long-time supporter NASGP. Her charity, Cuba Medical Link, enables medical students to go to Cuba for their electives.

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