According to Ben Goldacre, “the placebo effect is one of the most fascinating things in the whole of medicine”. If you’re not convinced, we hope these 20 facts about the placebo effect will change your mind:

  1. 97% of GPs prescribe placebos: A survey of UK GPs found that almost all of them have prescribed placebos. The placebos they prescribed were either pure placebos – treatments containing no active ingredients, e.g. sugar pills; or impure placebos – treatments with active ingredients, but that will not have an effect upon the condition e.g. antibiotics for a viral infection. (Check out our article on the subject to find out more). Sources: Research SummaryOriginal Paper
  2. “Until recently, the history of medical treatment was essentially the history of the placebo effect”: Until the invention of modern medicine, most treatments that have kept humanity alive for centuries were placebo treatments with no active ingredients. Source: The Powerful Placebo.
  3. Animals also experience the placebo effect: Several studies have found that animals can be conditioned to respond to placebos. For example, a study on mice with lupus, found that if mice were given medicine in sweetened water and then later, they were just given sweetened water, they would respond to the water as if it was the medication. Source: Original Study.
  4. You can get drunk on placebos: In a study, participants were given flat tonic water with a slice of lime and they were told it also contained vodka. Despite being just water, the participants still acted drunk and some showed physical signs of intoxication and impaired memory. Source: Original Study and a BBC article.
  5. Placebos can work even if you know they’re placebos: Researchers have found that if patients are given a placebo, but also told how and why placebos can work, they will respond to placebos as if it was an active medication. Source: Interview and Research Summary.
  6.  You can see the effects of placebos in the brain: Brain implants and MRI scanners have shown that neurons – the cells in the brain – can react to placebos the same way as they react to active medications.  This may not be true for every treatment, but there’s strong evidence that this is the case for pain relief and some neurological diseases. Source: The Placebo Effect in Clinical Practice.
  7. You can experience withdrawal effects from placebos: A study of over 8000 women discovered that you can experience withdrawal effects after taking the placebo long term. The trial looked at placebo pills compared to a type of hormone replacement therapy (HRT). The women took placebos (or the drug) every day for 5.7 years. When the trial ended, almost 5% of women on the placebo reported moderate to severe withdrawal symptoms. Source: Original Study
  8. There is more than one placebo effect: Research suggests that there are several ways that the placebo effect can work. These can be purely psychological or may also involve the immune or endocrine systems. Source: Placebo Effects.
  9. The more invasive, the better: The placebo effect can be made stronger: the more invasive the procedure, the stronger the placebo effect i.e. placebo surgery can have much stronger effects than a placebo that is rubbed into the skin. Source: Article.
  10. Two placebos are better than one: Taking two placebos can give you stronger effects than taking just one. Source: Article.
  11. Geography affects placebos: Where you live can affect how strongly you respond to different types of placebos. For example, a study found that placebos used to treat peptic ulcers had a 40% higher effect in Germany than Denmark and the Netherlands and Germans had a 54% stronger placebo response than Brazillians. But German’s are not super-responders to placebos, because they had one of the lowest responses to antihypertensive (blood pressure reducing) placebos. Source: Original Paper.
  12. The placebo effect can be responsible for 50% of a drug’s effectiveness: Almost every clinical study uses a group that has been given a placebo. Some studies also use a group that received no treatment at all. These groups can be compared to suggest how much of a drug’s effects are down to the placebo. Source: Article.
  13. More expensive = more effective: When people are given placebos with price labels on, they often feel that the higher priced placebo was more effective, even if they placebos are exactly the same. This also applies to generic vs. branded medication. Generic versions of branded drugs contain exactly the same active ingredients, but the packaging, cost and branding can influence how much people respond, making people feel stronger effects from the branded product. Source: Article.
  14. Colour affects placebo performance: Red, orange and yellow pills are better for stimulants; white, blue and green pills are more suited to tranquillisers. Colour may have other effects too that we don’t know about yet. Source: Academic Review.
  15. Personality may affect how you respond to placebos: If you have certain traits, you may be more likely to respond to the placebo effect that other people. This is great news if you’re a high placebo responder, because you may respond better to all treatments. Source: Academic Review.
  16. Psychiatric disorders are some of the most responsive conditions to the placebo effect: This can be as high as 30-50% of people in a study responding to a placebo. This can make it very difficult to understand how best to treat psychiatric disorders such as depression. Source: Academic Review.
  17. A bitter pill to swallow: Unpleasant, bitter tasting placebos have been found to have stronger effects than other placebos. Source: Academic Review.
  18. Taking a placebo can make you live longer: Studies have shown that committing to taking a placebo pill every day can have a positive effect upon your mortality rate, meaning you are statistically less likely to die and more likely to live longer. Source: Original Paper.
  19. Some people want placebos to be banned from sports: With the rise of complementary and alternative medicines being used by athletes (remember Michael Phelps’s cupping in the 2016 olympics), there’s been more investigation into how these therapies compare to placebos. With the exception of acupuncture, most of the therapies tested perform no better than placebos. With 73% of athletes admitting that they believed they had experienced the placebo effect in sport, this raises the question of whether placebos can give someone an unfair advantage in sport and some have called for a ban on placebos and alternative medicines. But if they work, placebos are the dopers-dream, as they’re completely undetectable. So they never could be banned in sport, but maybe it won’t be long before all athletes are making use of the placebo effect. Sources: Survey of athletes and BMJ editorial.
  20. The placebo effect is getting stronger: We don’t yet know why this is happening, but it could be because people now have more faith in medical interventions than they did before. But this also makes it much harder for new drugs to get onto the market, as they are usually compared to placebos to see how well they work. If they are not much better than the placebo, they will not be put into production. Source: Article

(Image by Jonathan Rolande, ‘Colourful Pills’)

5 thoughts on “20 facts you didn’t know about the placebo effect

    1. That’s definitely something we’ll be looking to do in the future. We’re hoping that they’ll be another blog post on each one. If you give us a follow, you’ll be notified when they’re up.

  1. I know that you may be trying to avoid upsetting anyone with this topic, but please understand that the unpopular reasoning can promote healthy debate when argued respectfully..and it IS your page not a democracy- let your “take” set the tone here!

    1. Thank you so much for your comment – we really appreciate some constructive criticism. You are absolutely right that we are being careful. We feel it’s important to let the science speak for itself on most things, but admittedly, we do have our opinions too – especially when we’re trying to write around the topic of the placebo effect. In some of these topics, we may be too cautious, because we can’t be backed up by science completely. But your comments are very true and we’re going to think about writing some proper opinion pieces for our blog to encourage more debate around these issues. We very much feel that a healthy discussion can make a big difference to everyone, but we are cautious about being too opinionated in case we inadvertently encourage people to engage in an unhealthy, unproductive way- but maybe that’s what moderators are for! So thank you for your comment – we’ll definitely look at how to share our opinions, encourage debate and to find our voice.

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