In a simple blind study, the project leader knows which drug I am taking. There is a good chance that the effect of the drug on me is triggered by the placebo effect. But why is my placebo effect alleviated if the project leader does not know what I am taking either?
In: 1
So in a modern clinical trial, the “project leader” is really the drug company. It doesn’t really matter (from a placebo response perspective) if they know who is on the drug or not because they don’t even know the names of the subjects. It is important for other reasons.
The importance of a double blind trial is that your *doctor* doesn’t know if you are on drug or not. The study doctor is going to be interviewing you about how you are doing – asking if your symptoms are getting better or not. If they know if you’re on the drug or not, it could bias the way they ask the questions which could bias how you answer.
For example, a doctor who knows you are on placebo might say “how are your symptoms? The same as last visit right?” A doctor who knows you are on drug might say “how are your symptoms? Are you feeling better?” People would tend to respond more positively to the latter.
In many trials, the doctor is actually assessing your symptoms. In depression studies the doctor might be “rating” your appearance and demeanor. If the doctor knows you are on drug or placebo this could impact their rating of you.
Latest Answers