placebo effect

The power of the placebo: how it works

We often mention placebos in this blog when we discuss research studies. The best studies use placebos as part of their design. The “gold standard” of research depends upon them. But do placebos work, and how?

Top research studies are called “double-blind controlled”. As one example, researchers randomly divide the study volunteers into two equal groups. If the research is to test if a new medication is effective, one group is given the real medication for the length of the study, and the other group is given a placebo. This looks and tastes the same as the real drug, but is just an inactive “filler”, without any biologic activity.

The person receiving the “medication” doesn’t know if he is receiving the real drug or the placebo, and if the study is double-blind, the researchers don’t know either, until the end of the study, when the code is broken, to find out who took what.

This research design minimizes bias, and gives more accurate results. To decide whether to release a new drug, the research needs to show that more people got a positive result from the real drug, than from the placebo. Due to the so-called “placebo effect”, typically about 30% of people taking the placebo, report that they feel better after taking the (inactive) placebo! Sometimes the percentage of people getting “better” from the placebo is greater than the percentage reporting improvement from the “real” medication.

Placebo effect getting stronger

An interesting phenomenon about placebos is that in the past 20 years, more people are responding positively to the placebo, in some cases as well to the placebo as to the real medication. The placebo effect seems to be getting stronger over time, and no one knows for sure why.

One of the top researchers in the study of placebos is an acupuncturist, Ted Kaptchuk, trained in China, and now part of Harvard Medical School.

How placebos work

Dr. Kaptchuk helped create the Program in Placebo Studies. One of their goals is to find out how they work. He emphasizes that the placebo effect does not happen for only one reason. People may feel better after taking an inactive pill for a combination of reasons.

Functional brain scans have shown that placebos may cause physiological changes in the brain, similar to the changes they may get from taking a “real” medication. People taking placebos may release endorphins from their brain, just like they would if there were taking a real medication.

Placebos work in only some conditions

Placebos are most effective when used for chronic pain conditions, fatigue, depression, anxiety, and chronic intestinal problems such as irritable bowel syndrome. Placebos do NOT work in conditions with physical pathology that is measurable. For example, in cases of tumors, cancers, and infections, placebos don’t work. Placebos only work in conditions that are strongly moderated in the brain, such as pain.

What Dr. Kaptchuk’s group found is that placebos work because they are part of the whole patient-doctor interaction. The medication is just part of the “ritual’ of medicine, which all help in healing: the white coat, the equipment in the office, the waiting room and the tools of the doctor, are all part of the rituals of medical healing, and all help the placebo work.

Placebos work best

as part of an experience with a truly caring doctor, who is empathetic, takes time, and shows real interest in the patient. This is another good reason to find a doctor who really cares for you.

If you want to find a doctor, of any specialty, anywhere in Brazil, check out our website:

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Esta postagem também está disponível em: Portuguese (Brazil)