People in control groups are usually given a sugar pill and are observed to assess if any changes occur to their health during the experiments. How do we know that these changes, if any, were the result of taking the sugar pill and not just random changes that might have happened even without taking the placebo? Are there any studies that prove that the placebo effect really exist?
In: 0
The basic answer to your question is “statistics”.
If you run a test on one person, anything you see could be caused by a lot a things. However, if you test tens, hundreds, or even thousands of people; the chance that there is something causing a major difference over the entire group of people grows increasingly unlikely.
THink about it like this: if you flip a coin 10 times and get 6 heads, that coin may or may not be weighted – but if you flip it 1000 times, and get 600 heads, it’s a lot more likely that coin is weighted.
…
To test the placebo effect, you divide a large group of people suffering some minor complaint into two groups. One group gets nothing, the other group gets “medicine” (usually sugar pills; sometimes another nonmedical substance). Then, you check back to see how each group did. And there are studies that show that the group that gets the placebo ends up doing better, on average.
The basic answer to your question is “statistics”.
If you run a test on one person, anything you see could be caused by a lot a things. However, if you test tens, hundreds, or even thousands of people; the chance that there is something causing a major difference over the entire group of people grows increasingly unlikely.
THink about it like this: if you flip a coin 10 times and get 6 heads, that coin may or may not be weighted – but if you flip it 1000 times, and get 600 heads, it’s a lot more likely that coin is weighted.
…
To test the placebo effect, you divide a large group of people suffering some minor complaint into two groups. One group gets nothing, the other group gets “medicine” (usually sugar pills; sometimes another nonmedical substance). Then, you check back to see how each group did. And there are studies that show that the group that gets the placebo ends up doing better, on average.
The basic answer to your question is “statistics”.
If you run a test on one person, anything you see could be caused by a lot a things. However, if you test tens, hundreds, or even thousands of people; the chance that there is something causing a major difference over the entire group of people grows increasingly unlikely.
THink about it like this: if you flip a coin 10 times and get 6 heads, that coin may or may not be weighted – but if you flip it 1000 times, and get 600 heads, it’s a lot more likely that coin is weighted.
…
To test the placebo effect, you divide a large group of people suffering some minor complaint into two groups. One group gets nothing, the other group gets “medicine” (usually sugar pills; sometimes another nonmedical substance). Then, you check back to see how each group did. And there are studies that show that the group that gets the placebo ends up doing better, on average.
one simple way, is you can add another group, that is given nothing. and then use them as the control group. and then in the test group, give half of them the real drug, and half of them the sugar pill and tell everyone they’re getting the real thing. then in this case, if the test group all had similar results, then your drug is no different than the placebo effect. this is called a “blind” study.
in a “double blind” study. even the researchers (except for a few) don’t know who’s getting the placebo. because even researchers acting differently could affect the results. in short, testing things on humans have so many variables outside your control. you do the best you can. and your data gets more accurate with more test subjects.
one simple way, is you can add another group, that is given nothing. and then use them as the control group. and then in the test group, give half of them the real drug, and half of them the sugar pill and tell everyone they’re getting the real thing. then in this case, if the test group all had similar results, then your drug is no different than the placebo effect. this is called a “blind” study.
in a “double blind” study. even the researchers (except for a few) don’t know who’s getting the placebo. because even researchers acting differently could affect the results. in short, testing things on humans have so many variables outside your control. you do the best you can. and your data gets more accurate with more test subjects.
one simple way, is you can add another group, that is given nothing. and then use them as the control group. and then in the test group, give half of them the real drug, and half of them the sugar pill and tell everyone they’re getting the real thing. then in this case, if the test group all had similar results, then your drug is no different than the placebo effect. this is called a “blind” study.
in a “double blind” study. even the researchers (except for a few) don’t know who’s getting the placebo. because even researchers acting differently could affect the results. in short, testing things on humans have so many variables outside your control. you do the best you can. and your data gets more accurate with more test subjects.
I’m actually not convinced that the placebo effect, as most people think about it, exists. That is to say, the idea that expectations of benefits from treatment leads to actual physiologically relevant changes. There are many effects that you see in the placebo group of a clinical trial, but I don’t think any are appropriately categorized as the sort of “mind over matter” placebo effect that most people think of.
Regression to the mean explains some of it. People in clinical trials are selected because they are in some way abnormal, when assessed at particular point in time. If you then reassess them later, in most cases the group will more closely resemble the average population, simply for statistical reasons.
Biases explain some of it too. For instance, the placebo effect is strongest for self-reported outcomes and tends to be minimal for more objective outcomes. There was a study looking at placebo inhalers in asthma. The placebo and the active bronchodilator produced similar subjective effects (patients reported feeling less breathless in both groups), but only the active bronchodilator actually improved objective measures of lung function. There is a placebo effect at play, but it’s to do with what the patient is reporting, rather than a change in physiology due to expectations of treatment.
These are just two effects that partially explain apparent benefits in the placebo group of trials. I suspect that the more statistical effects you control for, the smaller the placebo effect will be, and that there is no underlying relevant physiological change in most cases. There are several placebo effects (i.e. factors that explain benefits seen in control groups), but the placebo effect that most people think of isn’t really a thing.
I’m actually not convinced that the placebo effect, as most people think about it, exists. That is to say, the idea that expectations of benefits from treatment leads to actual physiologically relevant changes. There are many effects that you see in the placebo group of a clinical trial, but I don’t think any are appropriately categorized as the sort of “mind over matter” placebo effect that most people think of.
Regression to the mean explains some of it. People in clinical trials are selected because they are in some way abnormal, when assessed at particular point in time. If you then reassess them later, in most cases the group will more closely resemble the average population, simply for statistical reasons.
Biases explain some of it too. For instance, the placebo effect is strongest for self-reported outcomes and tends to be minimal for more objective outcomes. There was a study looking at placebo inhalers in asthma. The placebo and the active bronchodilator produced similar subjective effects (patients reported feeling less breathless in both groups), but only the active bronchodilator actually improved objective measures of lung function. There is a placebo effect at play, but it’s to do with what the patient is reporting, rather than a change in physiology due to expectations of treatment.
These are just two effects that partially explain apparent benefits in the placebo group of trials. I suspect that the more statistical effects you control for, the smaller the placebo effect will be, and that there is no underlying relevant physiological change in most cases. There are several placebo effects (i.e. factors that explain benefits seen in control groups), but the placebo effect that most people think of isn’t really a thing.
I’m actually not convinced that the placebo effect, as most people think about it, exists. That is to say, the idea that expectations of benefits from treatment leads to actual physiologically relevant changes. There are many effects that you see in the placebo group of a clinical trial, but I don’t think any are appropriately categorized as the sort of “mind over matter” placebo effect that most people think of.
Regression to the mean explains some of it. People in clinical trials are selected because they are in some way abnormal, when assessed at particular point in time. If you then reassess them later, in most cases the group will more closely resemble the average population, simply for statistical reasons.
Biases explain some of it too. For instance, the placebo effect is strongest for self-reported outcomes and tends to be minimal for more objective outcomes. There was a study looking at placebo inhalers in asthma. The placebo and the active bronchodilator produced similar subjective effects (patients reported feeling less breathless in both groups), but only the active bronchodilator actually improved objective measures of lung function. There is a placebo effect at play, but it’s to do with what the patient is reporting, rather than a change in physiology due to expectations of treatment.
These are just two effects that partially explain apparent benefits in the placebo group of trials. I suspect that the more statistical effects you control for, the smaller the placebo effect will be, and that there is no underlying relevant physiological change in most cases. There are several placebo effects (i.e. factors that explain benefits seen in control groups), but the placebo effect that most people think of isn’t really a thing.
You wouldn’t test an active ingredient against no treatment now because you wouldn’t know how much ,if any, of the effect came from the active ingredient. But there is nothing stopping people testing a placebo against no treatment since it’s the placebo effect you want to measure in that case, I presume.
Potential active medicines can be compared to a placebo *and* a control group that get no treatment at all (though nowdays they might get another already existing treatment perhaps) So the three groups could be compared. So that comparison between no treatment and a placebo treatment can be done if that’s what you were studying or may happen in normal trials. Of course a lot of research will be financed because it’s testing a possible active ingredient , testing placebos vrs no treatment seems likely a more ‘academic’ interest and possibly unethical if the participants were I’ll rather than being tested for something like response to painful stimuli.
Not only is there a placebo effect there is also a nocebo effect where the expectation of for example side effects can cause us to feel them. And quite a lot of work has been done on how the specifics of a placebo intervention can change the effect. For example the size and colour of a pill can an effect – but different colours have different effects in different cultures because of the meaning of that colour to them!
Placebos are particularly effective for conditions which involve a certain amount of interpretation and perception by the patient – for example pain. I think one of the areas still being explored is what the effect actually consists of internally. Physically a placebo seems to effect a mix of our autonomic ( not under our conscious control) nervous system, hormone production and immune responses. All things that our brain/body can do as responses to stimuli but we don’t necessarily do consciously. But significantly it’s the *expectation* rather than an actual *ingredient* that causes the effect.
I’m not a medical expert just find it interesting so I hope that makes sense and I havnt got anything significantly wrong.
Latest Answers