Placebo

A placebo (from Latin placebo "I will please") or placebo is a drug that usually does not contain a drug substance and thus has no pharmacological effect that could be caused by it. In an extended sense, other remedies are also called placebos, for example "sham operations".

Placebos serve as control substances in clinical research. Placebo drugs are used in placebo-controlled clinical trials in order to be able to record the medical/pharmacological efficacy of various procedures, each designated as verum, as accurately as possible, ideally in double-blind studies.

The use of placebos to treat symptoms of illness is ethically controversial, especially when it is not based on informed consent.

Placebo effects are positive changes in the state of health caused by a treatment with a placebo. In a generalized sense, this also refers to effects of treatments that are not sham treatments but can ultimately only produce the respective effect in the same way as a placebo. The counterpart to the placebo effect is the nocebo effect. These are undesirable effects that occur with apparent harmful substances that do not contain any harmful substance (e.g. electrosensitive reaction even when the mobile phone mast is switched off).

The effect of placebos is explained by psychosocial mechanisms. The partially reported effectiveness of some alternative medical procedures is also attributed to the placebo effect. Even with "conventional" treatments, effects can partly be explained by the placebo effect and sometimes doctors even use them specifically as placebos. However, whether and in which areas of application there really is a placebo effect is still disputed.

Etymology

The term placebo comes from the Christian liturgy. The Latin verse Placebo domino in regione vivorum (Ps 114:9 Vul) of the Vulgate translation of the Church Father Jerome, which follows the Hebrew text, reads in Luther's translation "I will walk before the Lord in the land of the living." (Ps 116:9 Lut84) - thus agreeing with the Vulgate translation. In the Septuagint, the ancient Greek translation of the Old Testament, on the other hand, the Hebrew verb for "go" or "walk" is not translated literally, but in a figurative sense. To this corresponds the Latin translation of Jerome after the Greek with the verb form "placebo"; the German translation of this verse reads accordingly: "I will please the Lord in the land of the living".

The derogatory idiom "to sing someone a placebo" derives from the funeral rite of the Catholic Church. The cause of this change in meaning in the late Middle Ages is thought to be, among other things, the changes in the design of the funeral service, which made it possible for the alternate chanting of this Vulgate verse to be intoned by paid singers and no longer just by the mourners themselves. "Placebo" was thus seen as something hypocritical, a flattering and spurious substitute performance.

Finally, in the 18th century, "placebo" became part of the medical vocabulary in its common meaning. The first lexical definition of the word was given by George Motherby in A New Medical Dictionary; or, General Repository of Physics (1775).

Placebo domino in regione vivorum, page from the Très Riches Heures

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Research

Placebos are used in research. Placebo-controlled, double-blind, randomized studies are used to closely examine the therapeutic efficacy of drugs. One part of the subjects receives the drug to be tested (verum), while the control group receives a placebo (identical in appearance, taste and, if necessary, side effects of the verum). A difference between the measured effects in both groups in favour of the verum can thus be regarded as its efficacy. This effect of the verum may be larger or smaller than the placebo effect. The statistical significance of the effect found in scientific studies and in favour of the verum (which in this context must necessarily be distinguished from the relevance of the effect of the verum) is one of the most important prerequisites for the approval of a drug by the competent health authorities.

• Double-blind studies are those in which neither the doctor nor the patients know whether placebo or verum was administered. This eliminates the possibility of influencing the outcome. The double-blind approach can pose challenges to the conduct of studies in which the verum is not in a form that can be easily converted to placebo. Their execution may then be imperfectly realized.
• Randomised means that the control group is determined by chance, for example by drawing lots. This avoids factors such as the stage of the disease being included unconsciously.

Placebotherapy

The placebo effect has a more or less large share in every treatment success. Pure or complementary placebo therapies are also not infrequently used in clinical practice. The administration of placebos for the treatment of complaints is ethically controversial. Especially in pain therapy, placebo effects can strongly support the treatment in a positive way.

How effective placebo effects can be for certain symptoms is shown by a study of patients with irritable bowel syndrome who received three placebo treatments of different intensities. The first group was studied only, the second received sham acupuncture and the last sham acupuncture in combination with empathic, attentive, trusting conversations. In the group with sham acupuncture, the symptomatology improved significantly compared to the untreated group, and in the group with sham acupuncture and additional talks, the improvement in symptomatology was once again significantly greater than in the group treated with sham acupuncture only.

The placebo researcher Bertrand Graz considers the correlation between the positive expectations of the physician and the healing success of a treatment to be so significant that he proposes a new name for this effect factor, curabo effect (curabo: Latin for "I will heal"), instead of placebo (Latin for "I will please").

According to a number of scientists, the placebo effect cannot be equated with spontaneous healing, even though it is suspected that similar biochemical processes can be observed in both. In a spontaneous cure, the body eliminates the disease without any knowing outside help. In the placebo effect, on the other hand, the body is stimulated by external influences that are supposed to have a reinforcing effect on healing. This thesis is opposed by the opposite opinion, according to which the placebo effect is exclusively due to spontaneous remission, natural fluctuation of symptoms and subjective influence of the results on the part of doctors and patients (see below).

Further areas of application

Another area of application in clinical practice is the maintenance of intake habits for an active substance that is administered intermittently (a typical example is the contraceptive pill, where one week per cycle the active substance is suspended).