If you have ever been blown on an injury as a child so that it would get better very quickly, you have gained early experience with the placebo effect. But how and why does it work? How effective the placebo effect can be.
Contents at a glance
What is the placebo effect?
A drug without an active ingredient is called a "placebo" or "placebo". According to Dr. Ulrike Bingel, pain researcher at the University of Hamburg, 20 to 90 percent of participants in relevant studies respond to placebos. For example, you feel pain relief even though the medication is drug-free. A placebo effect exists when a desired psychological or physical reaction occurs after the administration of a drug or other therapy, but this reaction is not due to active ingredients contained in the drug or a specific active principle of the therapy.
The effect does not only concern placebo drugs, which do not contain any active ingredients. Even "real" drugs can benefit from it, as the placebo effect can enhance their effect. Placebo effects also play a role in other therapeutic measures. Even after sham surgery or sham acupuncture, positive health effects can be observed.
How the placebo effect works
First and foremost, the placebo effect is based on two psychological mechanisms:
- The first active factor is Expectation of the patient towards the drug. Patients who have a conscious positive expectation of an administered medication have a better average effect than patients who do not have a positive expectation of efficacy. This applies to placebo drugs, but also to real drugs. The prescription by the physician and his explanation of the expected positive effect of the drug have a significant influence on the patient’s expectation of efficacy.
- The second effect factors are Experiences made so far with medications. If, for example, a real painkiller has helped reliably against pain in the past, the patient in question unconsciously assumes that a painkiller will also work well again. This leads in the sense of a conditional reflex to the fact that even a placebo without an active ingredient can help well against pain.
- In addition, other factors have an influence on the placebo effect: these include the color, shape or size of the placebo. For example, tablets, capsules and dragees in red tones are more likely to have a stimulating effect, while blue tones are more likely to be associated with a calming effect. In addition, placebos achieved a better effect in a study when the test subjects assumed they were receiving an expensive drug than when they assumed they were receiving a very cheap drug.
Various studies have shown that the placebo effect is also reflected in physical changes: For example, scientists at the University of Hamburg have found that the placebo effect influences pain perception in the brain. This effect can even be seen on MRI images.
Three brain regions in particular play a role here, which are involved in the body’s own inhibition of pain through endorphins – morphine-like substances secreted by the body itself. Real pain medications, such as opiates and opioids, also exert their effect via these three brain regions. The Hamburg scientists therefore suspect that placebo painkillers can trigger an endorphin release and in this way achieve their pain-relieving effect.
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Placebos: This distinction exists
Placebos are used in particular in clinical trials when a new drug is to be tested to see how it works. Then one part of the study participants receives the real drug and the other a placebo. However, the subjects are not told which group they are in. Due to the placebo effect, it is to be expected that the condition of the test persons in the control group (who received the placebo) will improve somewhat. The condition of the subjects in the intervention group (who received the active substance) should improve significantly more. Only then can you assume that the new drug has an independent effect that goes beyond the placebo effect.
A distinction is made between different groups of placebos:
- Real or pure placebos are placebo drugs that contain only pharmacologically ineffective substances and possible excipients to correct taste or color.
- Pseudoplacebos On the other hand, contain pharmacologically active substances, but in a dose that is too low for a noticeable effect or with a mode of action that has no known effect in the respective disease. The latter can be thought of as putting a band-aid on someone’s finger even though they have cut their foot. Pseudoplacebos are used in studies, for example, if the aim is to make the placebo taste more like the real drug or to ensure that a placebo causes side effects similar to those typically experienced by the real drug. In this way, for example, it can be prevented that study participants can assume on the basis of missing typical side effects that they are probably not in the intervention group. In this case, one also speaks of active placebos.
Does the placebo effect only work in case of ignorance?
That a placebo works for a patient who doesn’t know about it is easy to imagine. But the effect depends on ignorance? No, because scientists found that openly administered placebos can also help. However, it is important that, in addition to the information that a placebo is prescribed, a positive expectation of efficacy is again induced. This can be achieved by pointing out when prescribing that placebos have already helped many people with similar health problems.
Is the placebo effect also used outside of studies??
Physicians must always use effective therapies. Placebo administration is not permissible if there are measures that are more promising and are scientifically undisputed. If several equally suitable therapies are available, physicians should recommend the one that is expected to have the best healing success and the fewest side effects. If, under this premise, the use of placebos is a possibility, the physician must provide the patient with sufficient information so that he or she can weigh the pros and cons of placebo therapy on his or her own and thereby can make a free decision.
Since promising drugs and other therapeutic approaches are available for most diseases, placebos play a very minor role outside of studies. The placebo effect nevertheless has great significance for everyday clinical practice. It can be used to show the positive effects of prescribed drugs containing active ingredients once again noticeably increase. Therefore, doctors should ideally not simply fill a prescription, but also inform their patients exactly about the expected effect of the prescribed drug.