Updated: Jan 14th 2013
Placebo is hands down, one of the single most interesting things in all of science.
Basically, you fake a treatment for an illness (like a pill full of sugar instead of medicine) and the person gets better anyway. That’s pretty amazing, especially when you hear about it for the first time.
This has lead to a lot of rhetoric about “harnessing the power of placebo”. However, when you tease apart what the placebo effect actually is, it becomes a little less exciting.
In this post, we’ll discuss what exactly the placebo effect seems to be – and give some cool examples to show why people are so interested in it.
But then, we’ll make the following case: while the ‘placebo effect’ can (and probably should) be utilized by any healthcare professional as an adjunct to their treatment, there appears to be at least one major problem with giving someone ‘placebo’ as a treatment alone, even if it makes people feel better.
- Some fun examples.
- How big of an effect are we talking about here?
– Studies comparing something to placebo.
– Studies on the placebo effect itself.
- What is the placebo effect?
– the Placebo Effect
– the Nocebo Effect
- Here’s the problem…
– Disease vs. Illness: what’s the difference?
– Doesn’t the placebo effect actually speed healing?
– Why is this important?
- Yes, the placebo effect is still useful!
Some fun examples
Basically, the ‘placebo effect’ is what you experience when you receive a treatment that you believe is right for your disease or condition. We will elaborate on that later. First – what’s so interesting about it?
Let’s review some experimental results that you might find interesting (a.k.a. mind blowing when they were first published):
For gastric ulcers (those nasty, painful “stress ulcers” in your stomach), four sugar pills a day work better than two sugar pills a day! 1 There was no medication in any of them. Simply getting more “medicine” (or so the study participants believed) made their ulcers heal faster.
Crazy? Here’s more – pills are more effective when their colors “match” what they’re meant to do: for example, the same drug (oxazepam) is better at treating anxiety when it’s in a green pill, and better at treating depression when it’s yellow. 2, 3, 4 Since no ingredient changed, it’s clear that the cultural meaning of these colors had an effect on patients expectations – green is relaxing, and yellow is up-lifting.
But it’s not just pills – this happens with more complex treatments as well. And the more complex, the bigger the effect tends to be.
For example, saline (salt water) injections are more effective for pain than sugar pills. Not because the salt water does anything – it doesn’t – but because getting a needle seems like a more dramatic intervention to the patient! 5, 6, 7
Let’s kick it up another notch: surgery.
In one experiment, “sham” knee surgery was performed – which is basically cutting someone open and sticking surgical instruments inside without actually changing anything. The sham knee surgery actually worked just as well as the real procedure for improving peoples pain and function (as reported by the patients themselves). 8
Even sham surgery for angina (chest pain from lack of oxygen to the heart) is as effective as real surgery in making people tolerate more exercise with less pain. 9
Pretty cool stuff.
How big of an effect are we talking about here?
It depends. For example, you could simply give a placebo to a patient with very little information, or you could try to illicit the biggest placebo effect possible on purpose.
1. Studies comparing something to placebo:
When a treatment for a disease is first being studied, experiments are usually designed to compare its effectiveness against placebo. In these cases it’s really quite boring – you just gather a bunch of people, tell them they may get either the treatment or a placebo (but they don’t know – which is important), and then you measure their results afterwards. The hope is that the treatment works better than placebo – since any improvement in the placebo group could have occurred with giving them anything.
In these experiments, you’re basically telling them they might get something that doesn’t work. Here, the placebo effect has a small ‘effect size’ – meaning it may be noticeable, but it’s nothing to get excited about (like “meh, I kinda feel better, I guess”). 10, 11 In fact, some researchers believe a lot of this improvement is just because people usually get better anyway. 12
2. Studies on the placebo effect itself:
However, when people are actually studying the placebo effect itself, trying to find out what makes it stronger or weaker, it’s a different story. For example, in these experiments you may tell the patient: “you are going to receive an agent that is known to significantly reduce pain in some people” – which isn’t a lie (‘some’ could mean 5 out of 1000 people, and statistically ‘significant’ just means it’s not a fluke, but it doesn’t mean it’s a big effect).
When you say things like that – being confident and raising the patients expectations – the placebo effect is up to five times stronger, and has a ‘large’ effect size (like “yeah, I definitely feel much better”). 10, 11
It looks as though health care professionals who are confident and encouraging can raise the expectations of the patient and actually make them feel much better. In this way, it makes some sense to harness the “power” of the placebo effect. However…
What is the placebo effect?
Placebo – a treatment or intervention given to treat an illness – but which has no known active medicinal ingredients (a sugar pill, for example).
The Placebo effect – the effect one experiences when receiving a treatment or intervention that is believed to be appropriate for the given illness.
Therefore, you could experience a ‘placebo effect’ from either a placebo or something that actually treats the disease. It doesn’t matter, as long as it seems to be the right thing to do. The placebo effect has to do with the cultural tradition of being treated for an illness, and can be influenced by a ton of different factors. 13, 14 Cultural tradition? Sounds pretty flaky, but the more ritualistic a treatment seems, the more powerful the placebo effect seems to be. This is why it’s also known as ‘the meaning effect’.
There is even an opposite effect:
The Nocebo effect – yup, you can actually feel worse after a treatment that doesn’t actually do anything bad. If you think the treatment will cause harm, you may start focusing on anything negative and blame it on the treatment.
Ever read the side-effects of a medication and start thinking you might have them?
Healthcare professionals can also do this to their patients by using scary words. For instance, telling someone they have a “slipped disc” may cause more harm than good.
Here’s the problem…
If you read the examples above carefully, it starts to become clear that the placebo effect seems to only affect a persons feelings of illness. However, it doesn’t seem to have much of an effect on the underlying disease. 15, 21 For example, the ‘psycho-social support’ has a positive effect on cancer patients feelings of illness, but it does not improve how long they survive. 21
Disease vs. Illness: What’s the difference?
Disease – best refers to an abnormal condition affecting an organism. This abnormal condition could be due to infection, degeneration of tissue, injury/trauma, toxic exposure, development of cancer, etc. This is what needs to be ‘cured’, especially if it’s life-threatening.
Illness – best refers to the feelings that might come with having a disease. Feelings like pain, fatigue, weakness, discomfort, distress, confusion, dysfunction, etc. – the reasons people seek healthcare – and usually the way people measure their success with treatment.
It’s very important to understand that feelings of illness can be vastly affected by many non-disease factors, such as expectations, beliefs, fears, feelings/moods, and culture. Being ill is a very personal experience, and can vary tremendously and be affected by very different things between people with the same ‘disease’. While they obviously relate to each other in very significant ways, it’s important to understand the difference. (read: Disease vs. Illness for more detail)
Why is this important?
It’s important here because it seems the placebo effect doesn’t really affect ‘disease’.
The exception (in a way) are those ‘diseases’ whose mechanisms of development may have caused changes in the persons brain / nervous system, 14 like chronic pain, depression, or irritable bowel syndrome. In these cases, ‘psychosocial’ factors may have been a ’cause’ (or at least a strong contributing factor) of the current condition, and it makes sense to target those issues during treatment.
But that still doesn’t justify giving someone a sugar pill and telling them it’s an effective treatment. That’s just giving a placebo. However, it may justify utilizing the placebo effect, and may even be necessary for such illnesses. For instance, perhaps utilizing the placebo effect for chronic pain patients can reverse the brain changes associated with the condition. It may even be necessary.
Doesn’t the placebo effect actually speed healing?
People keep saying this, as if it gives the placebo effect a more objective basis. However, the evidence for this idea is not strong. And even when there does seem to be an effect on the disease process, it’s very indirect. Let’s use an example:
The studies cited above demonstrated that gastric ulcers heal faster with a more dramatic placebo. But there may be very good reason for this: stress. Stress has been shown to cause an increase in stomach acid, and the bacteria H. Pylori (believed to cause up to 90% of all stomach ulcers) thrives in an acidic environment. 16 Since we know that placebo can significantly lower stress, 17 it should be no surprise that placebo can speed ulcer healing. However, this doesn’t mean the placebo (sugar pill) actually killed the bacteria (disease)!
‘Irritable Bowel Syndrome’ is another good example. This condition causing pain and discomfort in the gastrointestinal system is highly related to psycho-social factors, namely stress. 18 Again, it makes perfect sense that stress relief will reduce symptoms. And a recent study reviewing the components of the placebo effect on this condition demonstrated that “the patient-practitioner relationship is the most robust component”. 19 If you have a healthcare practitioner that you trust, and you believe they will help you, you’ll feel better, and you will get better.
Placebos can also significantly relieve pain (as described in the examples above). However, we also know that pain doesn’t always mean there is tissue damage. Pain is another feeling of illness that can be manipulated by many other factors. See the ‘Pain Section’ of this site for more.
Yes, the placebo effect is still useful!
All this stuff isn’t to say that the placebo effect isn’t useful – it certainly is.
If you had pain or stress from a disease, you would want as much relief as you can get. ‘Illness’ is usually the reason people seek healthcare in the first place. As discussed above, it may even be necessary for some illnesses – but this justifies utilizing the ‘placebo effect’, not just ‘placebo’.
If we give treatments that are just placebo, then we might be making people feel better without actually treating their disease. This could be seriously dangerous.
This is why placebo is an area of debate in the world of healthcare ethics.
People are even trying to find ways to give a ‘placebo’ ethically – like in this experiment for example (again, notice all the outcome measures we’re subjective reports on symptoms – not an affect on the ‘disease’). 20 Personally, I find it funny that people are trying to find ways to give an ineffective treatment ‘ethically’. Again, why not simply give an effective treatment, and then utilize the placebo effect on top of that? Win-win.
Is it okay to take advantage of the placebo effect?
Within ethical guidelines, sure. I believe it is.
However, I do not believe it’s okay to take advantage of the patient.
Health care providers need to make sure they are doing everything in their power to treat the disease appropriately. The treatment should have good research to back it up: testimonials and anecdotes are not good evidence. Then the professional can worry about providing the treatment in a way that pleases the patient – to relieve stress and anxiety about their illness.
It should be simple, actually: the treatment should be discussed with the patient so they understand what’s going on, and can agree that this is the best choice for them. Some compassion from a practitioner who is informed, confident, and friendly might be all you need to “harness” the placebo effect.
The science of the placebo effect is very interesting.
In the end, perhaps it should be considered the icing on the cake?
What do you think?
This is a very opinionated topic – and I’d love to see how others feel.
All the references below, of course. Especially if you plan to debate the science with me in the comments below.
‘Why Bogus Therapies Seem to Work’ – this article is a fantastic reminder of why we should be humble in our claims as healthcare professionals, and constantly seek the best evidence available for choosing our treatments.
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