You’ve most likely heard of the placebo effect. In a nutshell, it’s the idea that a treatment with no active ingredients or proven medical benefit can still help your symptoms if you believe it will work. Placebos are probably best known for their use in clinical trial design – something to compare a new drug against – but you may not be aware that doctors really do prescribe “dummy drugs” or unnecessary procedures from time to time. Is this really a good thing?

What placebo treatments are doctors using?

The formal use of placebos in medicine dates back to the 18th century, though the concept itself is far more ancient.

Research in 2013 found that a staggering 97 percent of UK doctors had prescribed a placebo treatment at least once during their career. We’re not just talking sugar pills, though; it’s important to break down exactly what a placebo can mean in different contexts.

According to the survey results, published in PLOS ONE at the time, the majority of the respondents had used what is called an “impure placebo”. These are treatments or tests that are known to have some benefits, just not for the condition that’s actually being treated.

On the more benign end of the spectrum, this could mean prescribing a vitamin supplement when there’s no evidence it will specifically help the patient’s symptoms, or performing a physical examination to reassure them when one is not clinically indicated. The darker side would be something like prescribing an antibiotic for a suspected viral infection – not only will it not help the patient, but irresponsible use of these drugs is a major contributor to antibiotic resistance.  

More recent research in Australia found that 77 percent of responding GPs had used an impure placebo, the majority of which were antibiotics.

A “pure placebo”, in contrast, is what most people probably think of when they hear the term: a pill or injection containing only inert, non-pharmacological ingredients, like sugar or saline.

In both cases, the aim of treatment is to provide the patient with something, in the hope that the act of taking a medicine or undergoing an examination will be enough to help them feel better. And, at least sometimes, it seems to work.

What are some of the benefits of placebos?

In an article for the Montreal Gazette, cardiologist Dr Christopher Labos used the example of over-the-counter cold medicines to show how many of us already apply the placebo effect to ourselves.

“We all fall into this trap routinely. Many over-the-counter cold medications are clinically useless and yet we all regularly take them when we get sick,” Labos argues. “When we are sick, we all feel better when we do ‘something’ because doing ‘nothing’ is generally intolerable.” This is particularly acute when it comes to parents taking care of a sick kid.

We know that mental and physical health are intertwined, and scientists are learning more all the time about the effect that treating conditions like anxiety can have on overall wellbeing. If undergoing an unnecessary examination at the doctor’s office or taking a useless pill can help relieve a patient’s anxiety, it makes sense that their physical health might start to improve too.

There are studies covering the gamut of medical specialties that have found a positive role for the placebo effect in many conditions, from using colored overlays to improve reading, to treating Parkinson's disease.

Can you consent to a placebo?

One of the central principles in Western medicine is the idea of informed consent. It holds that patients should be given access to as much information as possible about a medical intervention, both the risks and the benefits, before making the decision to proceed with the treatment or not.

On the face of it, it’s tricky to see how giving someone a treatment that the doctor knows is ineffective could fit within this ethical framework. However, one curious thing about the placebo effect is that it seems to work even when patients know they’re getting a placebo. There’s no need for deception, and the patient can still give informed consent.

A small study in 2017 demonstrated this in patients given a placebo topical anesthetic before a heating plate was applied to their skin. There were three groups: some were told the cream was an anesthetic, even though it wasn’t; some were told that it was a placebo, and had the placebo effect explained to them; and some were given the placebo but with no explanation either way.

The group who thought they were getting an anesthetic reported a decrease in pain, as you might expect. However, the same was also true for the group who fully understood they were getting a placebo. The senior author on the study commented, “Openly administering a placebo offers new possibilities for using the placebo effect in an ethically justifiable way.”

An American Medical Association (AMA) Code of Medical Ethics Opinion addressing the use of placebos in the clinic stresses the need for patients to be informed about and consent to this type of treatment. It also states that the use of placebos should not be solely to “mollify a difficult patient”.

In other words, placebos may be used if the physician really believes they could benefit the patient, but not just for their own convenience and not in a way that undermines patient trust.

“First do no harm?”

Pure placebos, like sugar pills, are unlikely to actually cause any harm to a patient. The same cannot be said, though, for impure placebos. Like with any medical intervention, the risks associated with the treatment or procedure must be weighed up against the potential benefits.

We’ve already touched on this when it comes to antibiotic resistance, but there are lots of other examples where these kinds of questions come into play. Even something as seemingly simple as a vitamin tablet can carry a risk – one case report in 2022 described a man who was hospitalized due to excessive vitamin D, and some herbal supplements have been linked to liver injury.

Some doctors will order unnecessary tests to try and put their patients’ minds at ease, but interventions like X-rays – while broadly considered very safe – arguably shouldn’t be used with impunity. Even the simplest of blood tests carries a risk of bruising, clotting, and infection, however small.

Labos pointed to the fact that placebos are “not necessarily benign” as an argument against their use and highlighted that even if they don’t physically harm you, taking a lot of unnecessary medications imposes a financial burden on patients.

Some doctors just can’t get on board with embedding placebos in their clinical practice.

"Some patients may think anything that makes them better is a good thing, but the placebo effect is unpredictable and unsustainable. It’s not a practical treatment strategy," said Dr David Eidelberg, director of the Center for Neurosciences at The Feinstein Institute for Medical Research, in an interview with the Michael J. Fox Foundation.

“The idea that we can use placebos as a panacea for a range of health conditions is really problematic. It is bad for science and bad for patients,” Dr Chris Maher of the University of Sydney School of Public Health told the New York Times.

Maher is first author on a Perspective published in the Medical Journal of Australia arguing that the evidence supporting placebos is flawed and does not support their widespread clinical use: “It may be better to dismiss placebos and instead manage patients with evidence‐based treatments.”

It’s not the first time that the evidence basis for the placebo effect has been questioned. But while the practice has its detractors, it’s clear that many physicians have and do use placebos in certain circumstances.

As to whether they’re inherently good or bad, this is a question you’d be hard-pressed to answer for any medical intervention. If used in a different way, a drug that cures one person’s disease could easily kill another. Doctors always have to look at each patient’s unique, individual circumstances when recommending a course of treatment. And it would seem that for many of them, a placebo is an option that remains on the table. 

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current. 

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.