The Power of Placebo: When Surgical Benefits Are All in the Mind

Thought is a powerful thing, powerful enough to have dramatic effects on our bodies and health. Someone who is stressed out for an extended period of time may get chest pains, headaches, an upset stomach, or any number of other unpleasant symptoms (Though there are ways to be less stressed out using science). Their mental state is having a direct effect on their body. Our bodies tend to feel better when we are in a better emotional place, but I think the opposite of a stress headache may be something else: The placebo effect.

A lot of new "miracle cures" may in fact be the placebo effect instead. Image by Kaivasdeontologija. 

A lot of new "miracle cures" may in fact be the placebo effect instead. Image by Kaivasdeontologija. 

The placebo effect is the brighter side of mind over matter. A placebo is a medical treatment given that has no therapeutic effect on the human body. If, instead of taking ibuprofen for muscle pain, someone took a sugar pill instead, the sugar pill would be a placebo. It might seem that taking a dose of nothing much in particular might be pointless, but the placebo effect shows otherwise.

Even if a person is taking a placebo rather than a real medicine, their symptoms often show improvement. The brain associates the treatment with healing, and a physiological effect emerges. Our ability to feel better after taking a nonsense treatment is one of the reasons why new drugs are so thoroughly tested before being put into wide use. If a new medicine doesn’t improve symptoms better than a placebo, it may be nothing but a placebo itself.  

However, while it’s become commonplace to compare medicines to placebos, there are other medical treatments that generally go forward without this placebo testing. One field that rarely involves placebo testing is surgery. The idea of testing placebo surgeries may seem absurd, but given the risky nature of surgery, it is vitally important to make certain that surgical interventions do what they’re supposed to.

Placebo Surgery

Surgery used to be reserved for life-saving necessity, but more and more often, surgical procedures are used to improve quality of life instead. Fortunately, the increase in number of surgeries has been accompanied by an increase in the safety of surgery as well. In the 1940s, 64 – 100 people would die for every 100,000 that went under anesthesia. Today, mortality during surgery has decreased to between 0.4 and 1 per every 100,000.

So, if surgeries are so safe, why even bother testing them against placebos? First, if the placebo effect in response to medications is so strong, why would we not expect some element of placebo effect in surgery? Especially in cases where surgery is not provided for a life-saving reason, it may be that some people feel better in part because they expect to. Second, it is a tragedy if even 1 out of every 100,000 people die during surgery, and post-operative death rates are often much higher. Every surgery carries a risk, so it’s crucial make sure that each surgery performed is therapeutically necessary.

So what exactly would be a placebo for surgery? A couple years ago, Karolina Wartolowska, Andrew Judge, and their co-authors rounded up as many academic studies on placebo surgery they could find. They wanted to establish what trends were present across different trials involving placebo surgery, including both methodology and results.

They found that for the purpose of comparison, it was important for placebo surgery to duplicate the ritual involved in actual surgery. Patients fasted the night before, went through the process of surgery prep in the hospital, got sedated, and even received small incisions where surgery would normally be performed. In many cases, patients didn’t even know if they were getting placebo surgery or real surgery – though they all consented to take part in the studies and knew they might receive a placebo treatment instead.

Comparing the results of surgery and placebo surgery answered some questions, but raised others. In 74% of trials, people reported feeling better after placebo surgery. Real surgery was more effective at treating symptoms than the placebo in only 49% of trials, and in most cases the difference in benefit was small. For the other half, surgery and placebo treatments were similar in effectiveness. Serious adverse effects were seen in both the surgical and placebo sides of the study, but going through placebo surgery was in general much safer than getting the real thing and resulted in fewer side effects.

Looking at these results, it became obvious to Wartolowska and Judge: The placebo effect is present in surgery, and some clinical results of surgery may in fact be the placebo effect instead.


Though many of the studies highlighted in this paper were conducted years ago, there have been few changes in medical practice resulting from their findings. However, the results of these early experiments show without a doubt that without a group of participants experiencing a placebo version of a surgery, it is impossible to tell how much benefit is from the placebo effect.

So why is this happening? How can a surgeon cutting someone open and physically altering something be no different than an elaborate charade of surgery? There are a variety of factors that muddy the waters. One such factor is that many of the surgeries tested were for conditions that cause chronic pain. Chronic pain can wax and wane. If pain goes away after a surgery, it may just be part of the natural cycle of the condition rather than due to surgical changes.

Also, just because a part of the body appears damaged, doesn’t mean that it’s the source of pain. One of the most common surgical procedures repairs damage to the meniscus of the knee, but a study of over 300 MRI scans of knees failed to find any link between meniscus damage and pain. Studies of back pain found similarly poor correlations between spinal damage and pain.

 So why do we jump so swiftly to surgical procedures, even though the results are so murky? And should you rush out and cancel your upcoming knee replacement?

Not so fast. There are some conditions for which surgery is immediately necessary, like appendicitis. Just like it would be premature to release a new medication without testing it against a placebo, it would be premature to pull potentially life-saving surgical interventions off the table because other surgeries are not effective. A subset of surgeries are no better than placebos, but that doesn’t mean that all are.

It could be worse.

It could be worse.

Still, once a certain methodology becomes entrenched, it can be very difficult to break away from, even when evidence points in another direction. Hopefully the future will bring more research into the role of the placebo effect on surgery, so doctors can choose treatments that will get to the source of discomfort, rather than just tricking it away with the mind.

- Kate Dzikiewicz, Paul Griswold Howes Fellow