Why the placebo effect still has a place in modern medicine

Sham medical treatments can have real health benefits, and we can use this knowledge without compromising our ethics.

Lisa Shepherd
8 min readDec 12, 2022
Photo by Suzy Hazelwood on Pexels.com

For much of human history, our knowledge of medicine has been rather poor. Snake oil, bloodletting and trepanation are all once-popular treatments that we now know to be useless. Yet people really did report getting better from these treatments. Even today, there are plenty of medical treatments without an evidence-based leg to stand on that people swear have helped them. And they may well be telling the truth.

The power of placebo

A placebo is a substance or procedure that theoretically has no physiological benefit. Classic examples are sugar pills and saline injections. But it turns out if we believe something will help us, we’re likely to be right.

Pretending to perform knee surgery on people with osteoarthritis can bring as much pain relief as genuine surgery. People with Parkinson’s disease also respond positively to placebo interventions. The placebo effect is particularly powerful in the treatment of depression, so much so that it’s thought to account for 80% of the improvement conferred by antidepressants.

We even know that higher doses of fake drugs are more powerful. Two sugar pills are better than one, and larger capsules are perceived as stronger than small ones.

The placebo effect also has an evil twin, the nocebo effect, through which something becomes harmful because we believe it to be so. Most fascinatingly, the nocebo effect has been able to lend legitimacy to astrology. A study contrasted the causes of deaths of 28 169 Chinese Americans and half a million white Americans, and found that the Chinese Americans were more likely to die early if they had a combination of disease and birth year that Chinese astrology considered ill fated. No such association was found for the white Americans. The intensity of the effect was correlated with an individual’s commitment to traditional Chinese culture.

Although the placebo effect is still a bit of a mystery to us, the most popular theory is that it’s all down to our expectations. When you walk into a medical setting and get given a box of medicine, you expect that medicine to make you feel better. Expectations could trigger physical responses in a variety of different ways. Anticipating harm might lead to anxiety, while anticipating a positive effect could reduce anxiety and activate reward mechanisms. The placebo effect could also be down to conditioning. If you’ve been given medicines that eased your symptoms before, you’ll expect a sugar pill to do the same, and your body will respond accordingly. Think of Pavlov’s dogs, salivating because they heard a sound associated with food.

In some circumstances, a placebo may even be the best option. Some conditions don’t have particularly good treatments available, such as the common cold and certain types of back pain. If neither treatment is proven to help you, you may be better off going with a placebo than a drug that could cause unpleasant side-effects.

But would it be okay for your doctor to lie about your prescription, even if it’s the lie itself that heals you?

Ethics of the placebo

Doctors used to prescribe placebos with few reservations. In 1807, Thomas Jefferson claimed one of the most successful physicians he’d ever known “used more bread pills, drops of coloured water and powders of hickory ashes, than of all other medicines put together”. He described the practice as “pious fraud”.

Not all physicians were comfortable with dishonesty. In 1903, American physiologist Dr Richard Cabot described how he was encouraged to use sham treatments and stated, “I have not yet found any case in which a lie does not do more harm than good.”

Dr Richard Cabot

But until the mid-20th century, few doctors had such objections to deception. In a 1927 article titled Should Doctors Tell the Truth?, Dr Joseph Collins wrote, “The longer I practice medicine, the more I am convinced that every physician should cultivate lying as a fine art.” Unlike Dr Cabot, he called for physicians to take a utilitarian approach, arguing that when a lie was more beneficial to a patient’s health than the truth, the ethical choice was to lie.

Are placebos still used?

Sham medicines are no longer so easily prescribed. Today’s medical treatments are held to higher standards than ever. It isn’t enough for an expert to claim a medicine or procedure seems like it should work. We need to perform clinical trials to check new treatments aren’t completely useless — or worse, harmful. Even in those clinical trials, it’s rarely considered ethical to use placebos as a control. Instead, we compare new treatments to the current best option.

Lying to patients has also grown rather unpopular. The professional code of the American Medical Association instructs physicians to “be honest in all professional interactions”. (In case you’re curious, the code didn’t say anything about honesty until 1980.) In the UK, NHS workers have a duty of candour.

Truthfulness is important in medicine. You’re on the internet — it won’t take you many clicks to find people who “don’t trust doctors” or “don’t believe in conventional medicine”. Deceiving patients isn’t going to help matters. If your doctor prescribes you antibiotics for your cold, then yes, you genuinely may as well go with a chunk of rose quartz instead. But when someone comes down with a more serious affliction, you’ll want them to put their trust in a GP, not a homeopath.

Yet doctors do still prescribe placebos. In a 2012 survey, 12% of GPs in the UK admitted to having used pure placebos, such as sugar pills and saline injections, at least once in their career. More surprisingly, 97% had prescribed impure placebos. An impure placebo was anything unproven to be an effective treatment for a patient’s condition. These included antibiotics for viral infections, complementary and alternative medicine (CAM), unnecessary nutritional supplements and non-essential diagnostic examinations (e.g. blood tests). 77% of GPs said they prescribed an impure placebo at least once a week.

Why do doctors prescribe placebos when modern ethical codes emphasise honesty? Are they just willing to lie to patients for their own convenience?

For most doctors in the survey, there was no disconnect between their morals and their actions. 66% of respondents believed prescribing pure placebos was sometimes ethical, and 84% felt that impure placebos were sometimes acceptable. The most common justification for prescribing placebos, given by more than half the respondents, was to induce the psychological effects we’ve already discussed.

Photo by Negative Space on Pexels.com

It is, however, important to note that 82% of doctors believed it was wrong to prescribe a placebo while deceiving the patient. Most doctors described the treatments in optimistic yet honest ways, such as “This therapy has helped many other patients”, “This treatment promotes self-healing” and in about 10% of cases, simply “This is a placebo”.

But wait — wouldn’t telling the patient about the placebo make it useless?

The honest placebo

It turns out the placebo effect is more complicated than we once thought. Research now suggests that a treatment can heal someone even if they know it’s a placebo. Such treatments are called open-label placebos.

In one study, people with irritable bowel syndrome (IBS) were offered medicine described as “placebo pills made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes”. After three weeks of taking the pills, these participants reported significantly greater relief from their symptoms than people who received no treatment. Open-label placebo treatment can also reduce fatigue in cancer survivors, relieve chronic lower back pain and reduce pain during migraine attacks.

It turns out no deception actually needs to be involved for the placebo effect to work. It’s enough for your GP to tell you — with perfect honesty — that a treatment is likely to ease your symptoms.

Health professionals would be wise to consider placebo effects even when handing out medicine that’s proven to work. By creating positive expectations, reducing patient anxiety and ensuring a patient feels cared for, placebo can act as an additive effect. Little changes in phrasing, like “Here’s some medicine to help you get better” rather than a blunt “Here’s your medicine” could make treatments more effective.

We may scoff at homeopaths and other practitioners of alternative medicine, and they certainly deserve criticism, but they’re successful for a reason. It isn’t just about the treatment; it’s about the ritual. Alternative medicine practitioners are excellent at talking up their treatments, even if they’re just water, and they’re likely to have more time for you than your GP.

I live in the UK, where the NHS faces enormous strain. In the NHS Staff Survey, just 43% of staff said they were able to meet all the demands on their time at work, and only 27.2% believed there were enough staff at their organisation for them to do their jobs properly.

GP surgeries are overworked and understaffed. If I need medical advice, I’m unlikely to get an in-person appointment unless absolutely necessary. My GP surgery encourages me to submit an online form detailing my symptoms, or failing that, to book a telephone appointment. I then go down to the pharmacy to collect my prescription, with the only exchange of words being my personal details and a few pleasantries.

Of course this kind of consultation has advantages, but the placebo effect teaches us that the human element is important. Our medicine is more likely to help us if a professional assures us it will; if someone we trust makes us feel understood and cared for. It’s much harder to achieve the same effect with remote consultation. And even if you do manage to get an in-person appointment, how much time and compassion can you demand from someone who’s at their limit?

Medical ethics may have evolved, but so has our scientific knowledge. We can use placebos to help patients without needing to deceive them. It’s also important to remember the placebo effect is important in any medical treatment. Improvements in drugs and surgical procedures themselves are not enough to make medicine the best it can be. With pressures on health services increasing across the world, we must make sure to remember the importance of ritual.

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Lisa Shepherd

Science writer with a passion for all things biology.