Placebo Effect Psychology: Definition And Examples

Updated October 12, 2018

Medications can provide relief from symptoms of a wide variety of illnesses. Many of them also carry serious side effects. Wouldn't it be nice if there was a way to get the benefits of medication without the harmful effects of a strong medication? In some cases, there might be. It's called placebo effect psychology, and it might be more effective than you think.


What Is Placebo Effect In Psychology?

The placebo effect is an interesting term psychologist, and other scientific researchers use to describe a reaction to being given something that's supposed to help with a health problem. The origin, history, and definition of the placebo effect can help you understand more.

Word Origin

The word "placebo" comes from the Latin word "placebo," meaning "I shall please." Early in the 13th century, it was used to refer to the rite of Vespers in the Office of the Dead. The exact phrase used was "I will please the Lord in the land of the living," from Psalms in the Bible. In those days, the phrase was associated with an attempt to please by false means.

The first recorded use of the word in its current sense came from 1785 when it was described as "a medicine given more to please than to benefit the patient." Before that, any commonplace method or medicine was considered a placebo.

Placebo Effect Psychology Definition

So, what is a placebo effect in psychology? Placebo effect psychology refers to a beneficial effect that happens due to the person's belief that they'll receive a benefit. The placebo drug or treatment has no properties of its own that would generate this positive result, so it's assumed that the benefit comes only from the mind's power.

What Is Placebo?

If a placebo effect psychology definition refers to a reaction, what is the placebo itself? A placebo psychology definition would usually refer to a fake drug which has no ingredients that are expected to bring about the relief of symptoms on their own. In other words, the drug has no active ingredients.

However, a placebo isn't necessarily a fake drug. It could be a fake treatment of any kind, including pills, injections, procedures, or lifestyle changes. A placebo appears like the real treatment. If it's a pill, it has the same shape, size, and color. It feels the same and tastes the same.

History Of The Placebo Effect

In the 1500s, Ambroise Pare suggested that the most important part of the physician's job was to console the patient. Starting in the 1700s, though, the goal shifted more towards consultation and later to laboratory science to help people with their physical ailments.

Doctors used techniques and medicines that would now be considered placebos. These included pharmaceutical syrups, sugar pills, and other morale-boosters. By 1903, Richard Cabot suggested that the use of placebos was too deceptive to be ethical. Others said placebos not only didn't work but could be harmful.

Between 1880 and the 1920s, Emile Coue suggested that "the Placebo Effect" was effective. He approached his apothecary patients by praising the medicines he gave them and attaching a notice of their effectiveness. His book Self-Mastery Through Conscious Autosuggestion recommended a placebo effect centered approach as well.

In 1799, John Haygarth tested the placebo effect with medical treatment of the day called "Perkins tractors." He proved that a substitute treatment worked just as well as the real treatment. In 1920, the placebo effect was defined by scientist T.C. Graves as an effect that happened with drugs. Since then, scientists have used placebos extensively to compare the results of taking a non-medicine or dummy medicine with real medicine.

Does the Placebo Effect Cure Illness?

Through the years since placebos were first used, there's been much controversy over whether they work. As it turns out, placebos seem to be effective only in certain cases and for certain types of illnesses.

Doctors aren't allowed to prescribe sugar pills these days, but they can prescribe a medication that hasn't been proven to help with your particular illness. If the medication is mild and relatively harmless, your doctor may feel justified if she believes the placebo effect will help you.


Types of Symptoms Relieved

Placebos have been shown to relieve certain symptoms of illnesses. They may make you feel immensely better if you believe they will. Placebos are best for relieving symptoms like:

  • Pain
  • Stress-related insomnia
  • Cancer treatment side effects like fatigue and nausea
  • Anxiety

What Placebos Can't Do

Placebos have not been shown to cure illnesses. They can relieve certain symptoms. If the person believes in them strongly enough, placebos can be very effective for even severe symptoms. However, the underlying illness is still there. There's no evidence that a sugar pill can cure a disease like cancer. It can make the symptoms of illness far more bearable.

What Conditions Do Placebos Help Most?

Placebos help most with illnesses that are marked by symptoms that are helped by placebos. If your condition is one that mainly shows itself in the form of pain, a placebo might make you feel like you've been cured.

What Is The Nocebo Effect?

Nocebo effect is a term associated with the placebo effect. It refers to negative effects that happen when you're given a drug or other treatment that has already been shown to not affect, such as a pill with no active ingredients. If you're given a placebo and experience side effects, that's the nocebo effect in action.

How Do Scientists Use The Placebo Effect?

Scientists use placebos when evaluating the effectiveness of real medications. By comparing the effects of the placebo to the effects of the active-ingredient medication, researchers can find out how much of the improvement is due to mental processes and how much is due to the chemical properties of the medication.

Usually, drug trials using placebos are double-blind trials. This means that neither the doctor nor the patient knows whether the treatment is a placebo or the real thing.

Why Does The Placebo Effect Work?

Many possible reasons have been given as to why a placebo might work. Here are some of the possible reasons behind this phenomenon:

  • People expect it to work, so the interpret their symptoms differently.
  • People have positive experiences with medication and become so conditioned to the response that they have it even after the active ingredient is withdrawn.
  • The mind works with the body to bring relief by releasing endorphins or by other means.

Examples Of Placebo Effect Psychology

Because placebos have been used so extensively in research, there are many placebo effect psychology examples.

Does It Help To Just Take A Pill, Any Pill?

For a long time, scientists thought that placebos were only effective if the person taking them didn't know they were fake treatments. However, a 2014 study of migraine sufferers showed that placebos could be effective even if the person taking them is told they are getting a placebo. Those who took the real drub Maxalt had better results than the placebo group did.

The surprising outcome was that those who took the placebo had less migraine pain than those who got neither Maxalt nor the placebo. The study concluded that 50% of the drug's effect was due to the placebo effect.

Atrial Fibrillation

In a clinical trial of Warfarin, researchers gave people with chronic atrial fibrillation Warfarin, aspirin, or placebo. There were 335-336 in each group. The difference in outcome between the Warfarin group and the other two groups was dramatic: 20 taking aspirin and 21 taking placebo had strokes or other complications, only 5 taking Warfarin did. This told researchers that Warfarin was effective in reducing the risk of these complications. Interestingly, it also showed that aspirin was no better than placebo.


In a study of cancer drugs, three groups of about 350 cancer patients each were given two cancer drugs along with another cancer drug in low or high dose or a placebo. The goal was to find out if the additional cancer drug gave any additional benefit. Those who took the new drug, whether in low or high dose, had better results than those who took only the placebo.

While this study didn't directly measure the placebo effect, it does leave room for its possibility. Among those receiving the real medicine, 30-34% benefitted, but 20% of those who received the placebo also benefitted. Still, those who benefitted from the placebo may have been helped by other factors not measured.

Parkinson's Disease

One study sought to find out how placebos improved the conditions of people with Parkinson's Disease. Through PET scans done on patients given a placebo, scientists discovered that their brains released dopamine in response to the placebo. Although the Parkinson's had caused damage in their brains, the placebo was able to activate the dopamine system.


Irritable Bowel Syndrome

Irritable bowel syndrome is a fairly common disorder that causes gastrointestinal problems like abdominal pain, diarrhea, and constipation. In a test of placebo effect psychology, people with irritable bowel syndrome were given no treatment or a placebo acupuncture treatment with or without supportive interaction with their doctor.

Both placebo groups had better results than the group with no treatment. It's also important to note that those who received supportive care from their physician along with the placebo had the best results of all.


Researchers wanted to know if an antidepressant worked better than a placebo in relieving unipolar depression. Subjects were given either fluoxetine or placebo. PET scans of their brains showed something amazing. Both groups had increased glucose metabolism and limbic-paralimbic activity in their brains, and this reduced their symptoms of depression.

The placebo wasn't quite as effective as the fluoxetine, though. The antidepressant also brought about other brain changes in the subcortical and limbic metabolism that may have brought additional relief of symptoms.

Is There Another Way To Harness The Power of The Mind?

The placebo effect can bring many positive results. Taking a placebo can decrease symptoms of physical and mental disorders. It can make you feel more positive because you're doing something towards overcoming your condition.


Many people dislike the idea of taking a fake drug or other treatment. They may wonder, "if the treatment isn't real, how can it help me?" Many clinical trials use placebos, and most people in the trials accept that fact. They may feel differently, though, if they're given a placebo when they go to their doctor for real help.

Placebos are just one way to harness the power of your mind. Therapy is another means of using the power of your mind to overcome mental conditions. You can also benefit from therapy when you're dealing with serious physical ailments. The real treatment you get in psychotherapy can give you a more positive attitude. It can help you learn techniques like relaxation techniques and mindfulness that help you deal with symptoms of any disorder as well. Also, the support of a therapist can help you feel stronger as you face your condition.

You can talk to a licensed mental health counselor for help in dealing with a wide range of mental and physical conditions at You'll be paired with a counselor right for you. Through convenient online therapy, you can overcome your symptoms and develop more mental strength.

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