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The mind can trick you into believing that a fake treatment has real therapeutic results, a phenomenon known as the placebo effect. In some cases, placebos can exert an influence powerful enough to mimic the effects of real medical treatments.
In this phenomenon, some people experience a benefit after the administration of an inactive lookalike substance or treatment. This substance, or placebo, has no known medical effect and can be in the form of a pill (sugar pill), injection (saline solution), or consumable liquid.
In most cases, the person does not know that the treatment they’re receiving is actually a placebo. Instead, they believe they’ve received the real treatment. The placebo is designed to seem exactly like the real treatment, yet the substance has no actual effect on the condition it purports to treat.
The placebo effect is much more than justpositive thinking, however. When this occurs, many people have no idea they are responding to what is essentially a sugar pill. Placebos are often used in medical research to help doctors and scientists discover and understand the physiological and psychological effects of new medications.
Here’s why the placebo effect is important, how it happens, and why it works.
Placebo vs. Placebo EffectIt is important to note that a “placebo” and the “placebo effect” are different things. The term placebo refers to the inactive substance itself, while the term placebo effect refers to any effects of taking a medicine that cannot be attributed to the treatment itself.
Placebo vs. Placebo Effect
It is important to note that a “placebo” and the “placebo effect” are different things. The term placebo refers to the inactive substance itself, while the term placebo effect refers to any effects of taking a medicine that cannot be attributed to the treatment itself.
Causes of the Placebo Effect
Although researchers know that the placebo effect is real, they do not yet fully understand how and why it occurs. Various factors might contribute to this phenomenon.
Hormonal Response
One possible explanation is that taking the placebo triggers a release of endorphins. Endorphins have a structure similar to that of morphine and other opiate painkillers and act as the brain’s own natural painkillers.
Researchers have demonstrated the placebo effect in action using brain scans, showing that areas with manyopiatereceptors were activated in both the placebo and treatment groups.Naloxone is an opioid antagonist that blocks both natural endorphins and opioid drugs. After people received naloxone, placebo pain relief was reduced.
Conditioning
Other possible explanations includeclassical conditioning, or when you form an association between two stimuli resulting in a learned response. In some cases, a placebo can be paired with an actual treatment until it evokes the desired effect.
For example, if you’re regularly given the same arthritis pill to relieve stiff, sore joints, you may begin to associate that pill with pain relief. If you’re given a placebo that looks similar to your arthritis pill, you may still believe it provides pain relief because you’ve been conditioned to do so.
Expectation
Expectations, or what we believe we will experience, have been found to play a significant role in the placebo effect.People who are highly motivated and expect the treatment to work may be more likely to experience a placebo effect.
A prescribing physician’s enthusiasm for treatment can even impact how a patient responds. If a doctor seems very positive that a treatment will have a desirable effect, a patient may be more likely to see benefits from taking the drug. This demonstrates that the placebo effect can even take place when a patient is taking real medications to treat an illness.
Verbal, behavioral, and social cues can contribute to a person’s expectations of whether the medication will have an effect.
Genetics
Genes may also influence how people respond to placebo treatments. Some people are genetically predisposed to respond more to placebos. One study found that people with a gene variant that codes for higher levels of the brain chemical dopamine are more prone to the placebo effect than those with the low-dopamine version. People with the high-dopamine version of this gene also tend to have higher levels of pain perception and reward-seeking.
The Nocebo Effect
Conversely, individuals can experience more symptoms or side effects as a response to a placebo, a response that is sometimes referred to as the “nocebo effect.” For example, a patient might report having headaches, nausea, or dizziness in response to a placebo.
The placebo effect can be used in a variety of ways, including in medical research andpsychology researchto learn more about the physiological and psychological effects of new medications.
In Medical Research
In medical research, some people in a study may be given a placebo, while others get the new treatment being tested. The purpose of doing this is to determine the effectiveness of the new treatment. If participants taking the actual drug demonstrate a significant improvement over those taking the placebo, the study can help support the claim for the drug’s effectiveness.
When testing new medications or therapies, scientists want to know if the new treatment works and if it’s better than what’s already available. Through their research, they learn the sort of side effects the new treatment might produce, which patients may benefit the most, and if the potential benefits outweigh the risks.
In Psychology Experiments
In a psychology experiment, a placebo is an inert treatment or substance that has no known effects. Researchers might utilize a placebocontrol group, which is a group of participants who are exposed to the placebo or fakeindependent variable. The impact of this placebo treatment is then compared to the results of theexperimental group.
Even though placebos contain no real treatment, researchers have found they can have a variety of both physical and psychological effects. Participants in placebo groups have displayed changes in heart rate, blood pressure, anxiety levels, pain perception, fatigue, and even brain activity. These effects point to the brain’s role in health and well-being.
Benefits of Using a Placebo
The major advantage of using a placebo when evaluating a new drug is that it weakens or eliminates the effect that expectations can have on the outcome. If researchers expect a certain result, they may unknowingly give clues to participants about how they should behave. This can affect the results of the study.
To minimize this, researchers sometimes conduct what is known as adouble-blind study. In this type of study, neither the study participants nor the researchers know who is getting the placebo and who is getting the real treatment. By minimizing the risk of these subtle biases influencing the study, researchers are better able to look at the effects of the drug and the placebo.
One of the most studied and strongest placebo effects is in the reduction of pain. According to some estimates, approximately 30% to 60% of people will feel that their pain has diminished after taking a placebo pill.
For example, imagine that a participant has volunteered for a study to determine the effectiveness of a new headache drug. After taking the drug, she finds that her headache quickly dissipates, and she feels much better. However, she later learns that she was in the placebo group and that the drug she was given was just a sugar pill.
Placebo Effect Outcomes
While placebos can affect how a person feels, studies suggest that they do not have a significant impact on underlying illnesses. A major review of more than 150 clinical trials involving placebos found that placebos had no major clinical effects on illnesses. Instead, the placebo effect had a small influence on patient-reported outcomes, particularly of perceptions of nausea and pain.
However, another review conducted nearly 10 years later found that in similar populations, both placebos and treatments had similar effects. The authors concluded that placebos, when used appropriately, could potentially benefit patients as part of a therapeutic plan.
A Word From Verywell
The placebo effect can have a powerful influence on how people feel, but it is important to remember that they are not a cure for an underlying condition.
Healthcare providers aren’t allowed to use placebos in actual practice without informing patients (this would be considered unethical care), which reduces or eliminates the desired placebo effect.
10 SourcesVerywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Eippert F, Bingel U, Schoell ED, et al.Activation of the opioidergic descending pain control system underlies placebo analgesia.Neuron. 2009;63(4):533-543. doi:10.1016/j.neuron.2009.07.014Bąbel P.Classical conditioning as a distinct mechanism of placebo effects.Front Psychiatry. 2019;10:449. doi:10.3389/fpsyt.2019.00449Brown WA.Expectation, the placebo effect and the response to treatment.R I Med J (2013). 2015;98(5):19-21.Hall KT, Lembo AJ, Kirsch I, et al.Catechol-O-methyltransferase val158met polymorphism predicts placebo effect in irritable bowel syndrome.PLoS One. 2012;7(10):e48135. doi:10.1371/journal.pone.0048135Colloca L.The placebo effect in pain therapies.Annu Rev Pharmacol Toxicol. 2019;59:191-211. doi:10.1146/annurev-pharmtox-010818-021542Hróbjartsson A, Gøtzsche PC.Placebo interventions for all clinical conditions.Cochrane Database Syst Rev. 2004;(3):CD003974. doi:10.1002/14651858.CD003974.pub2Howick J, Friedemann C, Tsakok M, et al.Are treatments more effective than placebos? A systematic review and meta-analysis.PLoS One. 2013;8(5):e62599. doi:10.1371/journal.pone.0062599Peciña M, Bohnert ASB, Sikora M, et al.Association between placebo-activated neural systems and antidepressant responses: Neurochemistry of placebo effects in major depression.JAMA Psychiatry. 2015;72(11):1087. doi:10.1001/jamapsychiatry.2015.1335Kam-Hansen S, Jakubowski M, Kelley JM, et al.Altered placebo and drug labeling changes the outcome of episodic migraine attacks.Science Translational Medicine. 2014;6(218):218ra5-218ra5. doi:10.1126/scitranslmed.3006175Hoenemeyer TW, Kaptchuk TJ, Mehta TS, Fontaine KR.Open-label placebo treatment for cancer-related fatigue: A randomized-controlled clinical trial.Sci Rep. 2018;8(1):2784. doi:10.1038/s41598-018-20993-yAdditional ReadingWeiner IB, Craighead WE.The Corsini Encyclopedia of Psychology, Volume 3. Hoboken, NJ: John Wiley & Sons. 2010.
10 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Eippert F, Bingel U, Schoell ED, et al.Activation of the opioidergic descending pain control system underlies placebo analgesia.Neuron. 2009;63(4):533-543. doi:10.1016/j.neuron.2009.07.014Bąbel P.Classical conditioning as a distinct mechanism of placebo effects.Front Psychiatry. 2019;10:449. doi:10.3389/fpsyt.2019.00449Brown WA.Expectation, the placebo effect and the response to treatment.R I Med J (2013). 2015;98(5):19-21.Hall KT, Lembo AJ, Kirsch I, et al.Catechol-O-methyltransferase val158met polymorphism predicts placebo effect in irritable bowel syndrome.PLoS One. 2012;7(10):e48135. doi:10.1371/journal.pone.0048135Colloca L.The placebo effect in pain therapies.Annu Rev Pharmacol Toxicol. 2019;59:191-211. doi:10.1146/annurev-pharmtox-010818-021542Hróbjartsson A, Gøtzsche PC.Placebo interventions for all clinical conditions.Cochrane Database Syst Rev. 2004;(3):CD003974. doi:10.1002/14651858.CD003974.pub2Howick J, Friedemann C, Tsakok M, et al.Are treatments more effective than placebos? A systematic review and meta-analysis.PLoS One. 2013;8(5):e62599. doi:10.1371/journal.pone.0062599Peciña M, Bohnert ASB, Sikora M, et al.Association between placebo-activated neural systems and antidepressant responses: Neurochemistry of placebo effects in major depression.JAMA Psychiatry. 2015;72(11):1087. doi:10.1001/jamapsychiatry.2015.1335Kam-Hansen S, Jakubowski M, Kelley JM, et al.Altered placebo and drug labeling changes the outcome of episodic migraine attacks.Science Translational Medicine. 2014;6(218):218ra5-218ra5. doi:10.1126/scitranslmed.3006175Hoenemeyer TW, Kaptchuk TJ, Mehta TS, Fontaine KR.Open-label placebo treatment for cancer-related fatigue: A randomized-controlled clinical trial.Sci Rep. 2018;8(1):2784. doi:10.1038/s41598-018-20993-yAdditional ReadingWeiner IB, Craighead WE.The Corsini Encyclopedia of Psychology, Volume 3. Hoboken, NJ: John Wiley & Sons. 2010.
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Eippert F, Bingel U, Schoell ED, et al.Activation of the opioidergic descending pain control system underlies placebo analgesia.Neuron. 2009;63(4):533-543. doi:10.1016/j.neuron.2009.07.014Bąbel P.Classical conditioning as a distinct mechanism of placebo effects.Front Psychiatry. 2019;10:449. doi:10.3389/fpsyt.2019.00449Brown WA.Expectation, the placebo effect and the response to treatment.R I Med J (2013). 2015;98(5):19-21.Hall KT, Lembo AJ, Kirsch I, et al.Catechol-O-methyltransferase val158met polymorphism predicts placebo effect in irritable bowel syndrome.PLoS One. 2012;7(10):e48135. doi:10.1371/journal.pone.0048135Colloca L.The placebo effect in pain therapies.Annu Rev Pharmacol Toxicol. 2019;59:191-211. doi:10.1146/annurev-pharmtox-010818-021542Hróbjartsson A, Gøtzsche PC.Placebo interventions for all clinical conditions.Cochrane Database Syst Rev. 2004;(3):CD003974. doi:10.1002/14651858.CD003974.pub2Howick J, Friedemann C, Tsakok M, et al.Are treatments more effective than placebos? A systematic review and meta-analysis.PLoS One. 2013;8(5):e62599. doi:10.1371/journal.pone.0062599Peciña M, Bohnert ASB, Sikora M, et al.Association between placebo-activated neural systems and antidepressant responses: Neurochemistry of placebo effects in major depression.JAMA Psychiatry. 2015;72(11):1087. doi:10.1001/jamapsychiatry.2015.1335Kam-Hansen S, Jakubowski M, Kelley JM, et al.Altered placebo and drug labeling changes the outcome of episodic migraine attacks.Science Translational Medicine. 2014;6(218):218ra5-218ra5. doi:10.1126/scitranslmed.3006175Hoenemeyer TW, Kaptchuk TJ, Mehta TS, Fontaine KR.Open-label placebo treatment for cancer-related fatigue: A randomized-controlled clinical trial.Sci Rep. 2018;8(1):2784. doi:10.1038/s41598-018-20993-y
Eippert F, Bingel U, Schoell ED, et al.Activation of the opioidergic descending pain control system underlies placebo analgesia.Neuron. 2009;63(4):533-543. doi:10.1016/j.neuron.2009.07.014
Bąbel P.Classical conditioning as a distinct mechanism of placebo effects.Front Psychiatry. 2019;10:449. doi:10.3389/fpsyt.2019.00449
Brown WA.Expectation, the placebo effect and the response to treatment.R I Med J (2013). 2015;98(5):19-21.
Hall KT, Lembo AJ, Kirsch I, et al.Catechol-O-methyltransferase val158met polymorphism predicts placebo effect in irritable bowel syndrome.PLoS One. 2012;7(10):e48135. doi:10.1371/journal.pone.0048135
Colloca L.The placebo effect in pain therapies.Annu Rev Pharmacol Toxicol. 2019;59:191-211. doi:10.1146/annurev-pharmtox-010818-021542
Hróbjartsson A, Gøtzsche PC.Placebo interventions for all clinical conditions.Cochrane Database Syst Rev. 2004;(3):CD003974. doi:10.1002/14651858.CD003974.pub2
Howick J, Friedemann C, Tsakok M, et al.Are treatments more effective than placebos? A systematic review and meta-analysis.PLoS One. 2013;8(5):e62599. doi:10.1371/journal.pone.0062599
Peciña M, Bohnert ASB, Sikora M, et al.Association between placebo-activated neural systems and antidepressant responses: Neurochemistry of placebo effects in major depression.JAMA Psychiatry. 2015;72(11):1087. doi:10.1001/jamapsychiatry.2015.1335
Kam-Hansen S, Jakubowski M, Kelley JM, et al.Altered placebo and drug labeling changes the outcome of episodic migraine attacks.Science Translational Medicine. 2014;6(218):218ra5-218ra5. doi:10.1126/scitranslmed.3006175
Hoenemeyer TW, Kaptchuk TJ, Mehta TS, Fontaine KR.Open-label placebo treatment for cancer-related fatigue: A randomized-controlled clinical trial.Sci Rep. 2018;8(1):2784. doi:10.1038/s41598-018-20993-y
Weiner IB, Craighead WE.The Corsini Encyclopedia of Psychology, Volume 3. Hoboken, NJ: John Wiley & Sons. 2010.
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