Placebo Effect

5.1 Placebos

According to “The Placebo Effect” by Anne Harrington (6), a placebo is “(…) an inert sugar pill, active drug, or any treatment no matter how potentially specific or by whom administered”. However, this definition suits mostly the use of the placebo effect for medical purposes. Nevertheless, this research was planned to follow the same techniques used in medical trials and practical medicine. According to other scientific articles, meaning responses elicited after the use of inert or sham treatment can be called the “placebo effect” when they are desirable.(1) This is basically the same definition considering that a “sham” of fake treatment is used to replicate the effects of a real treatment. Interestingly enough, many times the placebo treatment obtains better clinical results than the actual treatments. On the other hand, whenever a negative effect is produced when using a sham treatment, the treatment is called a “nocebo”

5.1.1 3.2 Placebo Effect

The placebo effect is the difference of outcome between a placebo treated group and an untreated control group in an unbiased environment. According to the book “Understanding the Placebo Effect in Contemporary Medicine”, a simple definition for placebo effect would be: “The form of a treatment without its substance” (7). These definitions however are very ambiguous because the placebo effect cannot be limited to a single application. Like the article Deconstructing the Placebo Effect and finding the Meaning Response said, although placebos clearly cannot do anything themselves, their meaning can (1).

In this way, placebos must not be limited to treatments; because the placebo effect is triggered by a meaning response that, according to the article by Daniel Moerman, “proposes a new way to understand (…) a broad range of human experiences”. One of these experiences, for example, has been tested on physical performance, obtaining improvements in endurance, speed and weight-lifting. (8)

This “human experiences” yet to be understood may include the mental processes that this research seeks to study and to manipulate using the placebo effect; specifically short-term memory mechanisms.

5.1.2 3.3 Expectation and Conditioning

The placebo effect is not limited to reproducing a certain effect on a patient; in many cases the placebo trials obtain better results than actual drugs, and the same stimulus in many patients may result in different responses from each one. Because of this, scientists have researched about the explanation for this phenomenon in the brain.

Two mechanisms have been suggested to explain the placebo effect in the brain: Expectation and Conditioning (9). The theory of expectation consists in the idea that the patient generates about a certain treatment (that is a placebo), and the effects that it will have. If the patient believes that certain treatment would have a certain effect on him, theoretically this would trigger the placebo effect expected. Physicians can use then the same sham treatment to treat multiple diseases, and they would get different results according to the expectation that the patient has. In a certain way, the expectation method is a bit uncertain about the effectiveness and strength of the placebo effect.

The conditioning theory explains that the placebo effect is a conditioned response of the brain. This means that a patient can be unconsciously treated with a fake treatment and it will still work. The method however; involves the administration of a real treatment and a gradual withdrawal substitution to a placebo. The placebo would still have the same effect as the real treatment, and it is not dependent on a cognitive expectation. The conditioning placebo seems to be more controllable, which is very useful when seeking a specific effect, often similar to the effect produced by real drugs, in a patient.

These two theories have been debated in the scientific community because it was not known whether the placebo effect was controlled by a cognitive knowledge and expectation of the treatment or by unconscious cognition. Despite that, some researchers have agreed that both mechanisms play roles in the placebo effect and they can achieve different results. (10)

Conditioned placebos for example, are administered to patients alternating the use of a real drug and a placebo, associating in the patient the effect of the real drug with the placebo. (11) The placebo could be used further replacing the real treatment. It has been proven in some cases that this mechanism results into longer-lasting treatments than the ones with an expectation mechanism. (12)

The placebo effect accomplished by expectation works differently. In this mechanism, the patient has to cognitively believe in the effects that a certain treatment, that in fact is a placebo, will provide him. Just by believing this, or having a cognitive consciousness that he will be administered a successful treatment, a placebo effect is triggered. Scientists that investigated furthermore this mechanism have found some interesting data about the effectiveness of placebos.

Like the following graphics shows, the effectiveness of a placebo can be affected by the color of the pills administered.

This happens because of the perceived effect of pills according to their color; or the expectation that a patient has towards the pills. According to a study about the effect that color has on pills, color like blue and green are

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