What is a placebo in an experiment

It also works without deception

A placebo is a dummy drug - it can still work. A Swiss study has now shown that placebos can even relieve the pain of test subjects, even though they know that they are not real drugs.

The effect was shown in an experiment by psychologists from the University of Basel and Harvard Medical School. 160 test persons were asked to place their forearms on a plate that slowly warmed up. A group of participants was then given a supposedly pain reliever ointment - but this was a placebo. Another group received the same treatment with a cream labeled placebo, with no further comment. The third group, on the other hand, had been explained by the scientists in advance about the dummy drug and how the placebo effect worked.
In this study set-up, the psychologists were able to compare whether a placebo works better if it is administered clandestinely (group with alleged painkillers) or openly (group with an educational talk). The surprising result: Both remedies alleviated the test subjects' pain to the same extent. "The previous assumption that placebos only work if they are administered using deception should be reconsidered," says first author Cosima Locher from the Faculty of Psychology at the University of Basel. The accompanying information and communication between patient and doctor are therefore decisive for the success of the sham treatment.

Legally and ethically controversial

The use of placebos is controversial. Legally, because doctors are obliged to use effective therapy. If, for example, a method other than the placebo is proven to be more successful, the dummy drugs should not actually be used. There is also an ethical problem when doctors deliberately lie to patients and pretend that they are administering an active ingredient, even though it is only a placebo.
The German Medical Association (BÄK) recommends the administration of placebos in three cases:

  • When no proven effective therapy exists
  • If the patient has relatively minor complaints, for example a slight runny nose, but still wants to be treated with medication
  • When there is a chance of success with placebo treatment

The Basel study could now open up new possibilities in practice. “The original study design makes it clear that open administration of placebo can also produce the well-known placebo effect. So you don't have to 'deceive', ”says Robert Jütte, Director of the Institute for the History of Medicine at the Robert Bosch Foundation. He played a leading role in the recommendations of the BÄK on how to deal with placebos. "In this way, ethical and legal concerns can be dispelled when it comes to the administration of pure placebos."
In his opinion, another finding that emerges from the study should not be neglected: The communication between doctor and patient could be just as decisive for the success of the therapy as the medication itself can be achieved through the administration of a sham medication - for example through an optimal therapeutic setting, ”emphasizes Jütte. "This is how the best possible treatment success is achieved to the benefit of the patient."

How does the placebo effect actually work?

The mechanism of action of the dummy drugs is not yet entirely clear. There are two psychological approaches to explanation: That associative model assumes that patients have an unconscious learning experience. They associate a certain drug with the fact that they feel better after taking it. For example, if you happen to have no stomach pain after drinking a cold cola, you may actually feel better the next time you have stomach problems as soon as you consume the cola.
At the mentalistic model expectations are crucial. If the doctor promises that the ointment will relieve pain, then sometimes it is enough to believe that it will get better soon so that you feel less pain.