The world is full of stories of miraculous healings: migraines vanish in an instant, serious illnesses go into remission, and critically ill patients get up and walk home to their loved ones. For much of history, such miracles were attributed to divine intervention — just as any other sudden changes in a person’s fate. Sometimes healing actually occurs due to prolonged medical treatment, but in some cases, it is thanks to the remarkable placebo effect. This is what we will discuss now.
Helping” Medicine
The history of the term “placebo” began long before the era of modern medicine. Moreover, it initially pertained not to health, but to death. In the Middle Ages, it referred to professional mourners—people who replaced grieving relatives at funerals, serving as a sort of surrogate for sorrow. Later, “placebo” came to denote an imitation of something real and eventually made its way into medicine.
For example, in the 16th century, philosopher Michel de Montaigne observed that simple attention from a doctor possessed miraculous power for some patients. Three centuries later, apothecary and writer John Quincy published Lexicon medicum, a comprehensive medical dictionary where placebo was defined as “an epithet given to any medicine intended more to please than to benefit.”
Today, the term “placebo” refers to a dummy used to replace an active drug or treatment. The “placebo effect” describes a situation where the dummy, which is physiologically inert, somehow proves effective.
The most common placebos are sugar pills that mimic tablets, but they can also be injection solutions, various procedures, and even surgical operations. Their distinguishing feature is the absence of real impact on the body.
A person believes they are receiving treatment, and the “treatment” shows results—typically short-lived and subjective ones.
The curiosity of doctors, both past and present, stems from the fact that the placebo effect, to varying degrees, affects everyone, except those with specific health conditions like organic brain damage. Furthermore, studies show that sometimes the effect occurs even if the patient knows they are receiving a placebo.
It’s important to clearly distinguish between these two concepts: placebo and placebo effect. The former refers to a substance or action specifically designed to mimic medical intervention, such as to study the mechanisms of suggestion or assess the effectiveness of real treatments. In the case of the latter, the circumstances of the placebo’s creation are less significant.
The placebo effect can sometimes be induced by substances that appear to be medications. These are sold in pharmacies, accompanied by instructions detailing the mechanism of action, pharmacokinetics and pharmacodynamics, and when and how to take them. A doctor might be entirely confident that they are prescribing genuine treatment, yet the substances in the medication are as effective as sugar pills. For various reasons, a person might feel better after taking it: subjectively or due to the course of the illness. Everyone remembers the joke that a cold goes away in seven days on its own, but with treatment, it only takes a week. However, the belief in the medication’s effectiveness has already taken root. This is why it’s so hard to convince friends and family that a particular drug doesn’t actually work—they have observed positive outcomes after taking it.
The “Harm” Principle
In addition to placebo, there is also nocebo, which translates from Latin as “I shall harm” or “I shall cause harm.” The nocebo effect is similar to the placebo effect but with negative consequences: it causes a deterioration in condition despite being physiologically inert.
The nocebo effect is often observed in clinical trials. Patients informed about the side effects of the tested substance report experiencing them more frequently. Simply knowing that a medication might cause dizziness statistically increases the number of reports of dizziness.
This effect is also seen with “Dr. Google”: a quick search of one’s symptoms can lead to discovering a whole array of serious illnesses. As a humorous song advises, “Never Google your symptoms.”
Faith and Reason
So, we have established that therapeutically, a placebo cannot have a direct effect on the body. Nevertheless, subjective experiences often suggest otherwise. Sometimes, after taking a placebo, the illness seems to recede. How can this be explained?
As proponents of evidence-based medicine often say, “Post hoc does not imply propter hoc” (after does not mean because of). To verify the effectiveness of a treatment, pharmaceutical companies conduct large-scale clinical trials, with the most reliable results coming from double-blind, placebo-controlled studies. This means that a certain group of subjects receives a placebo instead of the new treatment, and neither the patients nor the medical staff know who belongs to which group. This ensures maximum objectivity and “purity” of the results. We will discuss studies in more detail later.
In everyday life, people are prone to cognitive biases and errors. A person takes a pill, convinced of its effectiveness, experiences a satisfactory result, and their belief is reinforced. However, this outcome could be due to numerous factors.
Firstly, the effectiveness of treatment can be facilitated by our complex nervous system. For any drug to work, it must bind to specific receptors in the body and initiate a cascade of reactions and neurotransmitter exchanges. However, in some who believe in the drug’s effectiveness, this mechanism triggers on its own. The brain preempts: “Okay, we are about to receive a painkiller, and relief is coming.” The body, primed for a positive outcome, produces neurotransmitters, including those that genuinely reduce pain. Consequently, the individual feels better. Additionally, in response to severe pain, the brain synthesizes sedative substances, such as opioids like endorphins, which alleviate the condition.
Interestingly, tomographic studies have shown that taking a placebo activates several brain regions, including the prefrontal cortex. This is the main “cognitive” area of the brain responsible for processing information and forming expectations about various events.
Confidence in the effectiveness of a drug can be instilled by positive past experiences, the words of an authoritative doctor or someone else the person trusts, the high cost of the medication, its impressive appearance, or a convincing advertising campaign. Interestingly, large tablets are more favorably received than small ones, and injections are considered much more effective than pills. If a medication can only be obtained after a quest akin to searching for the Holy Grail, its effect is almost guaranteed to seem miraculous!
In all these cases, the placebo effect is explained by the person’s belief and conviction in a positive outcome.
Secondly, sometimes the results are influenced by accompanying actions during treatment. For example, if a headache is partly due to dehydration, a glass of water taken with the placebo can alleviate it. Humid air during inhalation with just saline solution or the old-fashioned “breathing over potatoes” can itself ease coughs and runny noses.
Thirdly, improvement after treatment might be unrelated to anything specific. The natural course of many diseases involves spontaneous remission, making it difficult to establish a cause-and-effect relationship in a single case.
Nonetheless, many researchers advocate for not dismissing the placebo effect but rather harnessing it. After all, it can alleviate a patient’s condition without causing side effects—an ideal remedy! But how can this effect be made more controllable?
Here, compliance can help—the patient’s adherence to treatment. High compliance ensures not only proper medication intake according to the doctor’s precise instructions but also adherence to diet, daily routines, and various other recommendations. Logically, if a patient genuinely trusts the doctor and follows the treatment plan, the treatment is likely to be slightly more effective, simply due to this belief.
For the Sake of Science
Although placebo treatments do not affect the course of a disease or its main symptoms, they can be beneficial. Throughout much of the 20th century, doctors frequently prescribed placebos as harmless remedies. Dr. Richard Clarke Cabot of Harvard Medical School wrote that he, like everyone else, “was raised… on the universal use of placebos, bread pills, subcutaneous water injections, and other means.” Until the mid-century, this was considered good practice: no physiological harm to the body, but significant benefit from the patient’s self-suggestion.
Over time, the perception of placebos shifted from being “safe” remedies, not due to their physiological effects but rather their lack of action: prescribing a placebo meant the doctor was consciously forgoing actual therapy. Nevertheless, according to a 2008 survey in the U.S., more than half of general practitioners “treated” their patients with such substances. This was primarily to reduce anxiety in patients who didn’t need real medication, as some people are overly concerned about their health when it’s not necessary.
Today, the use of placebos in practice is largely discouraged due to serious ethical concerns. However, placebos serve another important purpose, which we touched upon earlier: they are crucial in clinical research.
The number of placebo-controlled studies is increasing yearly, as reflected in the rising frequency of the term in scientific articles. Such studies are called placebo-controlled trials and are a vital part of testing pharmaceutical drugs.
In a placebo-controlled experiment, participants are divided into several groups, including an experimental group and a control group. The experimental group receives the new drug, while the control group receives a complete imitation, or placebo. The placebo matches the real drug in consistency, physical state, color, and administration method. Patients in both groups believe they are receiving genuine treatment—this is the only way to determine if there is a difference between the drug’s effect and the placebo effect. All other parameters in both groups are kept the same.
Thanks to placebo-controlled studies, researchers can compare not only the efficacy of drugs but also other characteristics, such as safety, by looking at the number of side effects in both groups. If the real drug group reports significantly more side effects than the placebo group, it indicates that these effects are not just nocebo effects but have an objective basis.
The use of placebos in scientific research dates back to the 18th and 19th centuries, although these were initially sporadic experiments. For instance, in the 19th century, British physician John Haygarth discovered that both placebos and the then-accepted method of treating rheumatism were equally effective, leading him to doubt the efficacy of the conventional treatment.
For a long time, the potential effectiveness of a drug was judged not by real experimental data (how many patients recovered or had their symptoms alleviated), but by the presumed mechanism of action. It wasn’t until the advent of evidence-based medicine, which relies on facts, that the need for some form of control became apparent. Placebos fit this need perfectly.
In the 1930s, the first series of clinical trials on healthy volunteers was conducted: they were divided into two groups, one receiving a real cold vaccine and the other a placebo. The results were surprising: both groups showed almost identical efficacy, casting doubt on the vaccine’s effectiveness.
In the late 1950s, placebo-controlled surgical operations began to be used. This had an interesting history. Some experimental data suggested that tying off the internal mammary artery alleviated heart disease symptoms. However, not all doctors recognized the benefit of this procedure, so several large studies were conducted. Some patients underwent the actual surgery, while others only had skin incisions. In the end, the recovery and overall well-being of participants in both groups were identical.
Since then, the rules for using placebos in scientific research have been revised, primarily from an ethical standpoint. In certain diseases, such as cancer, leaving patients without any help is unacceptable, so sometimes the effectiveness of a new treatment is compared to that of existing treatments. In many countries, laws require companies to conduct trials of new drugs and procedures following the principles of voluntary informed consent. This means participants are honestly told that some of them will not receive real treatment.
Perkins’ Magical Tractors
In the late 18th century, Dr. Elisha Perkins invented an instrument to treat rheumatism. These were two rods, one iron and one brass, pointed at one end and rounded at the other. They were to be applied to the skin, and the rods would supposedly “draw out” the disease from the body, hence the name “tractors” from the English word “tract” (to pull) and “tractor” (that which pulls).
This miraculous tool became immensely popular, selling for the equivalent of $500 per pair in today’s money. However, doctors and scientists were skeptical about its efficacy. They called Perkins a charlatan, and after placebo experiments and numerous exposés and satirical cartoons, these magical rods fell out of favor and were forgotten.
Nowadays, similar devices have reappeared in the form of various electric gadgets that promise to alleviate a wide range of problems through skin application. Unsurprisingly, many people report experiencing a “beneficial” effect from these devices.
Scientists still do not fully understand the physiological mechanisms behind the power of suggestion, but they have learned to carefully exclude it from scientific evaluations. The placebo effect has a very limited scope and is useful as long as it does not lead us to make risky health decisions for others. It’s one thing to prescribe a placebo to a healthy person to alleviate their anxiety — though even here there is room for ethical debate. It’s entirely different to rely on a placebo to cure a life-threatening illness.
