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Placebo

Placebo

Author: Katherine Williams
Description:

Identify placebos in experiments.

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Tutorial

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This is your tutorial on placebos. A placebo is a treatment that has no known therapeutic value. So there's nothing about the particular treatment that should make you feel better or worse. It's not known, at least. But somehow, it does. It's a way of simulating the treatment without actually giving the treatment. And it's used-- often, it's given to the control group as a way of adding onto the control because it's going to help with our blinding.

When you're participating in the study, a participant's beliefs about whether or not they're in the control or treatment group can influence the outcomes. For example, if I think I'm receiving a kind of experimental drug as my treatment, then I'm going to report to my doctor any potential change in my life or my body that I notice. If I get headaches, I'm going to tell him about that because I think it has to do with the drug.

Now, perhaps, I would have gotten the headaches anyways because my eyesight is bad, but because I think I'm on the drug, then I'm going to over-report my symptoms. And the reverse can happen. If you think you're in the control group and you're not receiving a treatment, then you're going to under-report.

Similarly, a doctor's beliefs can influence the outcomes, as well. If a doctor believes a patient is in the control group, they might not pay as much attention or care for them in the exact same way as if they thought they were in the treatment group. This can happen in other examples that aren't medically-related, as well.

In order to help control for that and to add to the blinding, sometimes a placebo is used. Its colloquially called a sugar pill sometimes, but nowadays, it's not actually made of sugar anymore. But it could even be like kissing an owwie, so when a mom kisses a kid's knee. There is nothing that should make the child feel better about that. You're not actually helping the cut or fixing in any way. But the child feels better because of the treatment they received.

Similarly, using a spray bottle for monsters. You feel better because you're doing something, not because you're doing something that's actually getting rid of monsters.

So with the placebo, it's very important to keep in mind that it has no known therapeutic value, but as we're going to see, sometimes there actually is a value to it. But it's not therapeutic, it's mentally part of the patient's reaction to it.

Now, the placebo needs to be as close to the real treatment as possible. So if your real treatment-- let's say we're studying different forms of aspirin, and we give one person an aspirin tablet, and we the other person an aspirin tablet. These two tablets need to look the same. Studies comparing different placebos have shown that when the labels look differently, there's different results.

So, for example, colored pills are more effective than white pills. If you give a person a white pill and you give a person a colored pill, the person with the colored pill feels better than the person with the white pill.

Similarly, capsules are better than tablets. If your placebo comes in a capsule form versus your placebo coming in a tablet form, the people receiving the capsule report that they feel better.

Colored capsules are better than white capsules. The same is true with the pills.

And then, finally, needles are significantly better than pills. So if your placebo was coming in the form of an injection, you're going to feel more of an effect than if you get that in the form of a pill. So because the results of the placebos are different based on what the placebo looks like and how it's delivered, it's really important that the placebo match whatever the treatment is.

Because you're trying to determine whether or not it's the treatment or the participant's beliefs in the treatment that cause a real effect, you want to make sure that they're the same. If your actual treatment is a pill, but your placebo is an injection, the results are not going to be comparable, and you're not going to be able to truly determine the effect.

The placebo effect is when the placebo-- the fake treatment-- causes a change in the outcome of the participant receiving it. So let's say we have a person A and a person B. And person A receives the real treatment. And person B received the placebo.

If at the end of the study both person A and person B report feeling better, then we know that it's not actually the medication that A received that made them feel better. It was just receiving some form of care because B never got any medicine, and still ends up feeling great. So the placebo effect is when even though he didn't get anything special, he still ends up feeling better. There's some sort of, just, reaction to receiving a treatment.

So if at the end of the study both person A and person B end up feeling better, then it's really hard to conclude that the treatment-- whatever medication A received that B did not-- was the cause of this. Perhaps it was just being taken care of, or going to the doctor so many times, or any number of other things that happened during the study. But it's not the medication because if it were, B wouldn't do better. So the placebo and the placebo effect really helps us to narrow down exactly what is effective and what is causing the outcome.

This has been your tutorial on placebos.

Terms to Know
Placebo

An inert drug or treatment given to the control group. It has no active ingredient in it.

Placebo Effect

The observed phenomenon whereby certain individuals will exhibit a desired response even when taking a placebo, which contains no active ingredient.