The Placebo Effect in Action: Research and Everyday Life

Medically reviewed by Dakari Quimby, PhD

“Placebo effect” is a term that describes improvements to a person’s physical or mental health after taking a placebo, or fake, treatment. In other words, people can experience tangible improvements in their health even from a sham treatment such as a sugar pill, simply because they believe it will work.

Research suggests that an estimated 35% of people experience the placebo effect, though rates are higher for some conditions more than others.

This article discusses the placebo effect, what is known and unknown about how it works, and its uses, benefits, and risks. 

Meaning of Placebo Effect

The placebo effect is a phenomenon in which some people experience a benefit after receiving a placebo treatment. It is rooted in the power of belief and expectation. When someone believes they are receiving a beneficial treatment, their body can respond in a way that produces genuine physical and psychological changes.

The placebo effect is seen in several conditions, including pain, depression, fatigue, allergies, Parkinson’s disease, and irritable bowel syndrome.

The mechanisms behind the placebo effect are still a subject of ongoing research, and experts believe it demonstrates the complex interplay between mind and body. A combination of factors likely play a role, including:

• Expectation: People who believe a treatment will work are more likely to experience positive results.

• Classical conditioning: A type of learning in which people associate a neutral stimulus (e.g., a placebo pill or a visit to a healthcare provider’s office) with a positive stimulus, such as symptom relief.

• Endogenous opioids: The placebo effect may stimulate the release of endogenous opioids, natural painkillers produced by the body, helping reduce pain and other symptoms. 
  

Researchers are investigating why some people are more responsive to placebos than others. Individual differences in brain chemistry, genetics, and psychological factors may play a role.

The placebo effect occurs more often with subjective symptoms, such as pain, rather than objective medical evidence, such as a tumor identified on a computed tomography (CT) scan.

In other words, a placebo treatment may help improve your pain, but it is not going to kill cancer cells the way actual chemotherapy drugs do. 

Unknowns in the Mind-Body Connection

Researchers have made significant progress in understanding the mind-body connection, but there are still many unknowns, including:

• The mechanisms behind how thoughts and emotions influence physical health

• How to harness the mind-body connection to improve health and well-being

• The role of epigenetics in the mind-body connection (e.g., how stress and trauma can affect gene expression)
  

Placebo Effect Uses in Medicine and Research

Clinical trials are a fundamental component of medical research when testing new treatments, such as medications or novel (first-of-its-kind) therapies. The safety and effectiveness of new treatments are tested in clinical trials before they're introduced to a wider population. The placebo effect helps researchers understand the efficacy and safety of the treatment(s) they are testing.

In clinical trials, some study participants—the control group—receive a placebo instead of the novel treatment. This serves as a baseline to compare the effects of the actual treatment, helping researchers understand the effectiveness and safety of the new treatment(s) they are testing.

An Ethical Dilemma

There is an ongoing ethical dilemma and debate within the research community regarding the use of placebos. Some research studies do not inform participants they will receive a placebo vs. the new treatment, and sometimes the researchers don't know this nor of interim results during the ongoing trial (double-blind studies).

In other studies, participants are told ahead of time that they will receive a placebo (open-label placebo). Open-label placebo studies can be beneficial for studying the placebo effect for certain conditions, such as chronic pain.

In some cases, the placebo effect can be so powerful that it leads to significant improvements in the control group, making it challenging to determine if the tested treatment is genuinely effective.

Despite the differences in methodology, double-blind and open-label studies show that the placebo effect is a real and powerful phenomenon.

In medicine, some healthcare providers may prescribe a placebo when a person has symptoms in which emotions play a role, such as chronic fatigue, pain, or depression. This way, the person is satisfied with having access to treatment without the risk of potential adverse effects of a drug they don’t necessarily need.

However, many healthcare providers do not engage in this practice. They are concerned that if the patient discovers they are taking an inactive treatment, it may damage the patient-provider relationship.

The American Medical Association’s Code of Ethics suggests that physicians should make decisions in partnership with patients regarding using placebos.

For example, a provider could explain to a patient with chronic pain that they can prescribe different medications, including one that is not pharmacologically active (placebo) to make a more definitive diagnosis or achieve a better understanding of their condition. This avoids deception and helps build patient-provider trust.

Examples of Common Placebo Medications

The two types of recognized placebo medications are:

• Pure placebos: A substance or treatment with no known therapeutic effect and is designed to look similar to real treatments, such as sugar pills, saline injections, and sham devices

• Impure placebos: A substance or treatment with some known therapeutic effect but is presented as having a more significant impact than it does, such as herbal supplements, vitamins, antibiotics for viral infections, and unproven complementary therapies
  

Words, phrases, and healing rituals can also act as placebos, initiating changes in a person’s brain and bringing positive effects without medication.

Healing rituals (e.g., taking a pill or receiving an injection) can also have a placebo effect. These rituals can trigger the mind’s healing response, even if the treatment is inactive. 

The patient-provider relationship also plays a vital role in the placebo effect. When a patient has a good rapport with and trusts their healthcare provider and the provider uses comforting language or provides reassurance, these verbal cues can elicit the placebo effect and lead to improved symptoms.

Downsides of Placebo Effect

While the placebo effect can have many positive benefits, adverse effects are also possible. The placebo effect can also lead to nocebo effects—adverse side effects that people experience as a result of their negative expectations about a treatment. 

A systematic review and meta-analysis of 12 clinical trials investigating COVID-19 vaccines found that 76% of adverse events (symptoms) reported by participants receiving placebo vaccines are attributable to the nocebo response.

In other words, people who did not receive the active vaccinations experienced symptoms caused by their negative expectations, such as headache and fatigue, rather than the vaccine itself.

People who anticipate adverse reactions to medications (including placebos) are more likely to experience them, even if the drug does not cause those symptoms.

Summary

The placebo effect is a phenomenon in which people experience a benefit after receiving a placebo treatment—a substance or treatment with no known therapeutic effect. The placebo effect is particularly effective for conditions with a psychosocial component, such as pain, headaches, and fatigue.

Ultimately, the placebo effect is a powerful demonstration of the mind-body connection. More research is needed to determine its long-term effects, benefits, and risks. 

Read the original article on Verywell Health.