Taking a sugar pill can sometimes lead to real improvements in health. How does believing in a treatment, even when it’s fake, trigger physical changes in our bodies?
In: Biology
I think most if not all of what we consider to be the placebo effect is actually regression to the mean.
It’s a bit misunderstood. For a given condition and a given treatment, the “placebo effect” is the difference in experienced symptoms between a group that receives a “blank” treatment (placebo) versus a group that receives no treatment at all. The reason you want to account for this is you want to be able to account for symptoms that improve just by the perception of treatment.
So take cancer for example. The “no treatment” and “placebo” groups would be expected to continue to get worse with time while a treatment group would be expected to get better. So maybe the no treatment group reports pain and tiredness. Maybe the placebo group says their pain isn’t as bad and they feel a bit nauseous but have more energy. The treatment group is puking their guts out but their tumor is shrinking.
The “placebo effect” is not that you gave them a sugar pill and their tumor mysteriously started shrinking, it’s that they’re attributing a perceived improvement in their symptoms to the treatment, despite the fact that they didn’t receive any. It could be that they’re having a better few days than normal and genuinely feel better, it could be that the psychological impact of supposedly receiving treatment actually improves some of their symptoms. But what it isn’t doing is actually treating anything.
And that’s the big misconception, some people take the “placebo effect” to mean we can treat some diseases with sugar pills, but that’s not really what it is. It’s that people will *associate* any reduction in symptoms with a treatment, even if they’re not getting better.
So part of the “placebo effect” is actually statistical, not biological.
Say you get 100 people, they currently have the flu (chosen because we don’t really have a cure for it). Most of them will eventually get better right? and because they’re sick right NOW, they’re likely at a worse period.
So they take a placebo, and the other half takes the drug. 50 of those placebo-people will naturally heal, some better, some will have complications. 50 of those drug-people will also naturally heal, and have complications.
So in the end both seem to have “positive effects”… (and the negative effects are often attributed to the disease/flu just getting worse normally). See: regression to the mean btw.
Even outside that, often people will compare their “bad days” with their “good days” and start attributing the placebo to the “good days” they’re having. (aka its a problem with self reporting)
(There are studies specifically about the placebo effect. That often show the person themselves say they’re doing better, but things like “how often did they cough up their lungs” didn’t actually change. So the patient had simply convinced themselves they were doing better)
Finally there is ofc the physiological affects. These often affect things like depression, pain perception, etc. Which are all mental-related (tho not always), so the body CAN do stuff about it.
P.S> See: Regression to the mean
P.S> See: Mass Hysteria also
Oh by the way. They don’t use sugar pills anymore. For some tests surgar provides the desired results. Don’t know what they use.
The answer to this is that it mostly doesn’t. The idea of a magical placebo that actually cures you is mostly a myth. We know this because the placebo effect is strongest for subjective self-reported outcomes like pain or perceived breathlessness but basically absent when we look at objective measurements like expiratory flow rate or blood work.
The reason for including a placebo arm in trials is to capture confounding effects not related to the specific treatment under evaluation (e.g. regression to the mean, patients changing their lifestyle simply because they are being treated, expectation bias on the part of researchers etc.)
Most medications simply work by triggering your nervous system to release, or not release different chemicals. So the placebo effect can cause your body to release those same chemicals.
The placebo effect is partly not an “effect” at all – it is a way of adjusting for [reversion toward the mean](https://en.wikipedia.org/wiki/Regression_toward_the_mean).
Many experiments and trials recruit people based on some temporary criteria. For example, in medical trials, subjects often have some disease that is being treated. Many diseases get better on their own without any treatment, so having a placebo group allows a researcher to observe the difference the treatment makes to recovery **over and above the natural improvement.**
In many other experiments, there can be other parts of participating which can influence what is being measured. For example, in weight loss trials, simply weighing someone regularly can have an impact on their eating habits (and weight), in psychological experiments, the act of talking through the questions of an instrument repeatedly over time can alter responses.
Using a placebo-controlled trial allows a researcher to put someone in exactly the same situation as the treatment group except for giving them the treatment. This tries to adjust for anything else imaginable that could get in the way of measuring the treatment effect (including the possibility of what most people mean when they say the placebo effect).
Here’s an interesting fact: there is also an nocebo effect ( thinking something will harm you does) and an anticebo effect (believing that a medicine won’t help you and so it won’t)
To be honest a lot of evidence of the placebo effect is showing there’s only really significant effects in measurements of subjective experience. i.e. testing how well painkillers work.
Other effects observing medicine “working” can be chalked up to things like having a functional immune system for recovery. For example, you could take a medicine that doesn’t work to treat your cold. Regardless of it working or not, you’re going to get better in a few days because it’s just a cold.
Sometimes people with cancer go into remission spontaneously. That is the “placebo effect” being tested against, the baseline level of recovery.
Guy who reads statistics papers sometimes.
It doesn’t. It’s a statistical artefact as far as we know.
If placebo did work then you could run an RCT, Randomized Control Trial, and see placebo outperform nothing. It’s simple: randomly separate patients into two groups, give group A nothing, give group B placebo. You would expect group B to heal faster, but it won’t.
Placebo effect is best explained by regression to the mean. It’s a very cool but intuitive concept. Extreme events tend to be followed by more usual events.
Imagine you take a group of ill kids and give them energy drinks. You will see a lot of them recovery fast. This is because the kids were very ill and most will become less ill with or without your energy drink.
Same happened with placebo. You give group A placebo. You give group B your new medicine. Group B recovers in X days. But group A recovers too. Whoa, placebo healed people! Not really.
Perhaps people knowing that they take some new medicine can be somehow affected by it. In that case placebo could be helping somehow. We just don’t see that happening
Latest Answers