Placebo effect: what is it, examples, and psychology

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Gina Allegretti, MD 

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Gina Allegretti, MD 

last updated: Aug 04, 2021

4 min read

Imagine waking up at night and feeling a sudden, sharp pain in your body. You wait for a few minutes, but it doesn’t go away. You start to worry—are you hurt? Are you sick? Is it serious? 

The next morning you sit anxiously in the waiting room of your doctor’s office and brace yourself, waiting to hear something scary. Your doctor greets you warmly, examines you carefully, and reassures you that everything is fine. Almost immediately, your fear and pain improve. You may not realize it, but you have just experienced the placebo effect. 


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What is the placebo effect? 

Just the knowledge that you’re being treated can make you feel better. This is known as the placebo effect.

There are many different types of placebos. You might be familiar with placebo pills, which contain non-medicinal substances like sugar or starch. 

Scientists often use placebos when testing the effects of a new drug. They’ll give half of study participants the active medication and then compare the outcome to a group given placebo pills. If there’s more improvement in the experimental drug group at the end of the study, researchers know the drug works. 

Placebos don’t have to come in pill form. Other examples include words, stories, healing rituals, and acupuncture. All of these can bring about positive effects in the body without using active medication (Kaptchuk, 2011).

Examples of how placebos are used 

There are many examples of the placebo effect’s benefits. Some studies suggest that placebos can elicit the same effect as certain drugs (Mayberg, 2002). The placebo effect won’t work for every condition, but below are some examples of its impact.

Pain relief 

Scientists identified a link between the placebo effect and pain relief decades ago. Early studies compared people given pain medication after a dental procedure to those given a placebo. Both groups felt the same amount of pain relief, meaning the placebo worked just as well as the pain medication (Levine, 1984). 

Just knowing that you’re receiving drugs for pain can alleviate symptoms. In another study, researchers gave hospitalized patients pain medication through IVs. Half of the participants were only told they were getting drugs, while and the other group received drugs but weren't told so.

Even though treatment was identical in both groups, those who knew they were getting pain relievers reported lower levels of pain than the other group (Benedetti, 2011). 


Many studies have shown that placebos can be just as effective as drugs used to treat depression. Although people with severe depression usually improve with medication, studies found those with mild or moderate depression reported the same improvement in symptoms whether given a placebo or an active drug (Fournier, 2010). 

Arthritis of the knee 

A study done in 2002 shook the orthopedic world. Surgeons and researchers took a group of 180 patients with knee pain and performed surgery on half the group and “fake” surgery on the other half.

The fake surgery involved real skin incisions, and participants didn’t know if the procedure had actually been performed. Both groups reported the same level of pain relief, meaning the placebo procedure was just as effective as surgery (Moseley, 2002).

Migraine headaches

Some believe the placebo effect only works if you don’t know you aren’t getting the real deal. As it turns out, you don’t actually need to believe you’re getting treatment for the placebo effect to work. 

One study found patients with migraine headaches had significant relief when treated with a placebo medication––even though they knew it wasn’t real. Those who took a placebo labeled as a medication had the same amount of pain relief compared to patients actually given the drug (Kam-Hansen, 2014).

How it works: the placebo effect and psychology

Your brain processes information about everything you do, and that applies to medical treatment.

There are psychological effects associated with every treatment, regardless if you experience physical effects or not (Benedetti, 2005). Scientists haven’t yet identified the exact reason why the placebo effect occurs. However, researchers have found many psychological factors that contribute to it.    

Personal expectations

When you take medication, you expect a result. If you receive treatment that you've heard was amazing and worked for everyone else, you're likely expecting it to work for you, too. This expectation can contribute to feeling like your symptoms have resolved (Benedetti, 2014).


Your brain learns associations based on past experiences. If you’ve taken a medication that’s helped every time you tried it, you’re conditioned to believe it will work (Murray, 2013).

Conditioning reinforces your expectations and makes them stronger over time. And there is tangible evidence that positive thinking works.

That said, expectations and conditioning are not always positive. If you’ve had negative reactions taking a particular medication in the past, you might experience the opposite of the placebo effect: the nocebo effect. In this case, your expectation that something won’t work reduces any benefits you could feel.

Social cues

The way you experience a situation can be influenced by the signals you interpret from people around you (Colagiuri, 2015). For example, if you’re participating in an activity and everyone else seems to be having fun and enjoying it, you’re more likely to enjoy it yourself.


Some people are more open to ideas and suggestions than others. Studies have shown that if you are more open to persuasion, you're more likely to experience a placebo effect (DePascalis, 2002).

How can you experience the placebo effect?

If you wished the placebo effect came in a bottle, you’re in luck. 

Meet Obecalp (hint: it’s just the word “placebo” spelled backward). This product is sold online and claims to offer all the benefits of a placebo in a convenient little pill. But you don’t need to buy anything to experience the placebo effect. 

You’re probably familiar with mindfulness activities––like meditation and yoga––that help harness the benefits of the placebo effect. In fact, some studies have shown that mindfulness is useful in treating anxiety and depression (Hoffman, 2010).

Even certain hobbies, such as gardening, knitting, coloring, or journaling, can improve mood and relieve stress––with absolutely no medicine required.  

Alternative therapies like faith healing rituals and acupuncture can also relieve pain without the need for drugs (Kaptchuk, 2011). Just knowing that someone is caring for you often works like medical care.   

Although some health conditions require drugs, in certain situations the healing power of the placebo effect is just as good as medication. More research may reveal just how this effect works.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

August 04, 2021

Written by

Gina Allegretti, MD

Fact checked by

Yael Cooperman, MD

About the medical reviewer

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.