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  • In 1996, 56 volunteers took part in a study

  • to test a new painkiller called Trivaricaine.

  • On each subject, one index finger was covered in the new painkiller

  • while the other remained untouched.

  • Then, both were squeezed in painful clamps.

  • The subjects reported that the treated finger hurt less than the untreated one.

  • This shouldn't be surprising,

  • except Trivaricaine wasn't actually a painkiller,

  • just a fake concoction with no pain-easing properties at all.

  • What made the students so sure this dummy drug had worked?

  • The answer lies in the placebo effect,

  • an unexplained phenomenon

  • wherein drugs, treatments, and therapies that aren't supposed to have an effect,

  • and are often fake,

  • miraculously make people feel better.

  • Doctors have used the term placebo since the 1700s

  • when they realized the power of fake drugs to improve people's symptoms.

  • These were administered when proper drugs weren't available,

  • or if someone imagined they were ill.

  • In fact, the word placebo means "I shall please" in Latin,

  • hinting at a history of placating troubled patients.

  • Placebos had to mimic the real treatments in order to be convincing,

  • so they took the form of sugar pills,

  • water-filled injections,

  • and even sham surgeries.

  • Soon, doctors realized that duping people in this way had another use:

  • in clinical trials.

  • By the 1950s, researchers were using placebos as a standard tool

  • to test new treatments.

  • To evaluate a new drug, for instance,

  • half the patients in a trial might receive the real pill.

  • The other half would get a placebo that looked the same.

  • Since patients wouldn't know whether they'd received the real thing or a dud,

  • the results wouldn't be biased, researchers believed.

  • Then, if the new drug showed a significant benefit compared to the placebo,

  • it was proved effective.

  • Nowadays, it's less common to use placebos this way because of ethical concerns.

  • If it's possible to compare a new drug against an older version, or another existing drug,

  • that's preferable to simply giving someone no treatment at all,

  • especially if they have a serious ailment.

  • In these cases, placebos are often used as a control to fine-tune the trial

  • so that the effects of the new versus the old or alternative drug can be precisely compared.

  • But of course, we know the placebos exert their own influence, too.

  • Thanks to the placebo effect,

  • patients have experienced relief from a range of ailments,

  • including heart problems,

  • asthma,

  • and severe pain,

  • even though all they'd received was a fake drug or sham surgery.

  • We're still trying to understand how.

  • Some believe that instead of being real,

  • the placebo effect is merely confused with other factors,

  • like patients trying to please doctors by falsely reporting improvements.

  • On the other hand,

  • researchers think that if a person believes a fake treatment is real,

  • their expectations of recovery actually do trigger physiological factors

  • that improve their symptoms.

  • Placebos seem to be capable of causing measurable change in blood pressure, heart rate,

  • and the release of pain-reducing chemicals, like endorphins.

  • That explains why subjects in pain studies often say placebos ease their discomfort.

  • Placebos may even reduce levels of stress hormones,

  • like adrenaline,

  • which can slow the harmful effects of an ailment.

  • So shouldn't we celebrate the placebo's bizarre benefits?

  • Not necessarily.

  • If somebody believes a fake treatment has cured them,

  • they may miss out on drugs or therapies that are proven to work.

  • Plus, the positive effects may fade over time,

  • and often do.

  • Placebos also cloud clinical results,

  • making scientists even more motivated to discover

  • how they wield such power over us.

  • Despite everything we know about the human body,

  • there are still some strange and enduring mysteries,

  • like the placebo effect.

  • So what other undiscovered marvels might we contain?

  • It's easy to investigate the world around us

  • and forget that one of its most fascinating subjects

  • lies right behind our eyes.

In 1996, 56 volunteers took part in a study

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B2 US TED-Ed placebo drug painkiller effect pain

【TED-Ed】The power of the placebo effect - Emma Bryce

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    VoiceTube posted on 2016/07/22
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