A placebo is a inert or harmless substance that is used in place of an active medication or treatment. It may be given for psychological reasons, such as to ease the anxiety of patients who are undergoing medical procedures. Placebos are also given to research subjects in order to measure the efficacy of new treatments; the subjects must not know whether they are receiving the real treatment or the placebo so that their expectations do not bias the results.
The word “placebo” comes from the Latin phrase “I shall please”. The first recorded use of placebos dates back to 1785, when they were used by James Bruce while he was researching ways to treat malaria. He found that quinine, a bitter bark extract, was effective in treating the disease, but many of his patients could not tolerate its taste. So he gave them tasteless tablets made of bread crumbs and told them it was medicine; most got better within a week.
Since then, placebos have been extensively studied and their effects shown to be far more powerful than previously thought. In one famous study from 1955, researchers at Harvard Medical School gave patients with angina pectoris (a heart condition) either nitroglycerin (a medication known to relieve chest pain) or an inert placebo pill. They found that those who received the placebo experienced just as much relief from their symptoms as those who received nitroglycerin!
Placebos work by activating parts of the brain that control pain and other sensations; this release of chemicals reduces our perception of pain and makes us feel better. The power of placebos has been extensively documented in numerous studies over the past few decades. In one study, patients with irritable bowel syndrome (IBS) were given either a genuine medication or a placebo; both groups showed significant improvements in symptoms!
So why do placebos work? There are several theories: perhaps we believe we will feel better because we have been given a “medicine”; maybe we trust our doctor more when he/she prescribes us something; or maybe taking something – even if it’s just sugar pills – makes us feel like we are doing something proactive about our health which in turn eases our anxiety about being ill. Whatever the reason, there is no doubt that placebos can have very real and powerful effects on our bodies and minds!