Why does there have to be a plecebo/control group in a drug test?
In: Biology
Because what would you compare the results against?
If X number of people survived after taking the drug, how would you know how that compared to the number of people that survived without drugs.
In simple terms, you pick a substance. Gather a group let’s say 100 people. You give half the group the substance and the other half the placebo, like a sugar pill that looks identical to the actual substance. No one in the study knows which they were given. Then you collect the results through various means and compare.
1.) Sometimes just convincing people they are receiving a treatment may be enough to alter the results of a study. Gavin a placebo group controls for this by creating a group of patients who think they are receiving a study drug when they aren’t.
2.) Sometimes you just have random variation. Having a group that isn’t receiving the study drug helps analyze whether a study result could just be a consequence of random variation.
In a hypothetical real situation: if you had a experimental cancer drug that you gave to 100 people with cancer, and 50 of them were still alive a year later? Does you drug do anything?
Well that example is a bit flawed since there are variables that can be somewhat easily monitored. But something like an antidepressant may be different: just telling people they are receiving an antidepressant drug might alter their responses on follow up surveys, while some patients not receiving the drug or placebo might recover without it.
The idea is to test the effect of the specific drug, not the effect of administering… anything. The placebo is used to make the experience of the control group (i.e. the group not getting the drug) exactly the same as the experience of the group getting the drug; the only difference is the presence/absence of the drug itself. That makes the comparison a true test of the drug. Because the subjects don’t know which group they’re in, this is called a “blind” trial.
If the people conducting the trial know if a particular subject is getting the drug or the placebo, this might influence their behaviour when conducting the trial. (They might behave differently when administering the drug/placebo, or their knowledge might influence how they interpret the clinical results.) For this reason, the information about which subjects get the drug and which get the placebo should be hidden from the people conducting the trial until the results are finally analysed. Because both the subjects and researchers don’t know who’s in which group, this is called a “double-blind” trial.
Like all good experimental science, the whole idea is to design experiments that stop us fooling ourselves by our preconceptions, and instead to find out what’s really going on.
Humans are very complex, and one is a lot like another, but also very different from another. Does blood pressure medicine A lower my blood pressure the same amount it lowers yours?
And outcome measures can have a level of subjectiveness to them; weight is fairly objective, pain is not. And the observers/recorders often have conscious and unconscious biases that affect their reporting.
People who meet certain criteria enter into a study, and are randomized to the treatment group or the control group. They are randomized to increase the likelihood that other confounding variables that we don’t know about or didn’t consider in our inclusion criteria are equally balanced between the two groups. Ideally, neither the participants nor the observers know which group you are in, reducing the biases that can come from “I’m taking the active treatment” or “this person is taking placebo.” In the perfect study, the only variable that would be different in the two groups would the substance being tested. This increases the likelihood that any observed differences in the groups reflects an actual treatment effect rather than some other confounding variable(s).
The placebo effect (improvement in condition after taking a placebo) is as high as 20%; the human mind can be a powerful thing.
A parallel group to the those tested with the new medicine. They placebo group receive empty pills or injections but they are convinced they got the real deal. The researches are testing two things:
1) The psychological effect. Do people feel better just because they think the new medication is effective? Is it all in the mind?
2) In case people get side effects, it’s almost impossible to decide if these (sometimes severe) effects are caused by the medication. If a similar number of cases are detected in the placebo group, that’s a sign they are not caused by the medication. If complications are reported only in the group which received the real stuff, then they suspect the new drug is causing it.
For extreme simplicity, let’s call it drug x and drug y
Drug x seems to drop your happy ass like a log into a coma. But we can’t quite verify if it was the drug or some kind of external process happening. So we introduce a plecebo and see if the effects are real or faked.
I’m sure it’s a lot more complicated than this though.
There has to be a control for any scientific experiment. The control is what the results are compared to, in order for any conclusion to be accurate.
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