What is the Placebo Effect and How Does it Work?

For years, the placebo effect has been considered a hurdle towards producing good medicine. Now with its effects differing less and less from potential treatments, researchers are beginning to consider the effect as an important part of medicine instead of an obstacle.

What is it?

The placebo effect happens when a patient is given a fake drug, for example a sugar pill, to treat their illness. Then, believing that it should make them better, they see positive results.

How Does it Work?

Its exact mechanisms are not fully understood however researchers have found that placebos actually cause the release of opioids and other endorphins (chemicals that reduce pain). And this happens for a variety of reasons.


Trust seemingly plays a big role. One study for example shows that patients whose painkillers are given by a hidden robot pump at unknown times need twice as much of the drug for the same pain relief as when given by a nurse. Assurance from a trusted health provider or authority alongside a perceived treatment plan may help the placebo effect. 


Pharmacological conditioning is also important. In a 2012 study, patients were given a sweet drink containing an immune suppressant for a few days. After a certain period, the drug was swapped for a placebo. Despite the change, these people’s immune systems still behaved as if the drug was present. Researchers concluded that this was because they had learned to associate sweet drinks with decreased interleukin production, a key protein in our immune systems.


 A 2011 study tried treating asthma in four different ways. One group received an inhaler with albuterol, a drug that opens the airways. Another got an inhaler with a placebo, one got sham acupuncture and the last got nothing.

Patients in the first three groups reported a similar feeling of increased wellbeing following treatment although in reality, only albuterol improved airflow. This means that the placebo effect may be good at helping us ignore symptoms and focus on what could possibly be going right even if underlying problems persist.  

What About When Patients Know it’s a Placebo

Researchers at Harvard launched an experiment to see whether peoples’ symptoms improved even when they knew they were taking a placebo. Even among some of the hardest chronic conditions to treat like irritable bowel syndrome and lower back pain, symptoms improved.

According to expert Luana Colloca, this may have worked due to the difference between belief and expectation. Although patients may believe a pill won’t work, they still unconsciously expect it to because they’re taught from infancy that pills make them better.

What Does This Mean?

The placebo effect works by taking advantage of our preconceived beliefs on treatments and creating a hormonal response that can actually make us feel better. Although its exact workings are still unknown, the placebo effect could allow doctors to prescribe lower doses of addictive pain medication- something that could help reduce cases of overdose.

Annie Lennon

Writer with an insatiable curiosity for people, facts and places. Currently interested in learning more about making our way towards a blue economy.