November 12, 2012


Placebo is the term used to describe a medically ineffectual treatment. The placebo substances are medically inactive and they are used to induce a perceived or an actual improvement of the patient’s health, though no real treatment is actually taking place. For a better understanding of the term, doctors state that placebo is any therapeutic procedure that hasn’t been proved to have any specifical physiological or mental activity.

The first placebo clinical trials

The idea of the placebo in modern times originated with H. K. Beecher. He evaluated 15 clinical trials concerned with different diseases and found that 35% of 1082 patients were relieved by a placebo alone (“The powerful Placebo”, 1955). Other studies have shown that the placebo effect is even greater than Beecher claimed. For example studies have shown that placebos are effective in 50 or 60% of subjects with certain conditions.

Placebo can be:

  • Inert placebo, when it is reffered to an inactive medical substance, with a neutral content;

  • Active placebo, when it is used an active pharmacological pill, which is though not considered necessary and effective during the treatment of the specific affection.

Alternative uses of the placebo understanding

The placebo does not refer only to substances that seem to produce similar effects with the ones expected from a pharmacologically active substance. It refers to any procedure that is meant to have a great deal of influence upon people’s minds.

For example:

Forty years ago, a young Seattle cardiologist named Leonard Cobb conducted a unique trial of a procedure, at that time commonly used for angina. During this procedure the doctors made small incisions in the chest and tied knots in the arteries to try increase the blood flow to the heart. It was a very popular technique, with a 90% success. But, when Cobb compared it with a placebo surgery in which he made incisions but did not tie off the arteries, the operations proved to be just as successful as the regular ones.

It is very important to make the difference between the “placebo effect” and the “placebo response”. They are not synonimes, as many tend to believe. The “placebo response”, also known as the “felt placebo effect” is any change that takes place after the administration of a placebo, a change that can happen due to different reasons: a simultaneous treatment the patient hasn’t told the doctor about, the natural course of the disease, etc. The real “placebo effect” is that part of the “placebo response” that wouldn’t have taken place unless a placebo was given. This is why, during the clinical trials, besides the experimental group of people there needs to be a control group to which a placebo is given, as well and a third no-placebo group.

The placebo effect is known to depend on:

  • The relationship between the doctor and the patient;

  • The doctor’s medical experience and prestige;

  • The modern technological equipement inside the medical institution in which the clinical trial takes place;

  • The pharmaceutical form of the placebo substance.

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