the placebo effect

Dadface

I am assuming that volunteers who take part in drug trial testing are aware of the fact that they may be given placebos.Is it likely that this awareness may make the placebo effect less efficacious?

JonMoulton

In a clinical trial, a decrease in the placebo effect would be an advantage for the advocates of the treatment. If you are the group conducting the trial, you want to see the clearest difference possible between the placebo and the treatment. The placebo effect refers to the tendancy of people receiving a placebo to report amelioration of symptoms. This makes it more difficult to distinguish the difference between the placebo arm of the trial and the treatment arm of the trial.

If awareness of the possibility that a patient is receiving a placebo decreases the placebo effect, it will be easier to tell whether the drug is working or not when comparing data from the two trial arms.

Cincinnatus

Interesting, but this effect would be equal in both populations (placebo and drug). So it would not affect any inference you would draw.

Moonbear

Indeed, if the placebo effect were reduced, that would be a benefit in testing a novel drug since it too would have a reduced chance of getting a response due to placebo effect only.

In answer to the implied question, yes, if placebos are used, patients in the trial will be informed that this is a possibility. Although, unless something being tested is a novel drug for a condition that was previously untreatable, due to ethical considerations, usually placebos are not used for the control group. Instead, new drugs are usually compared against the existing treatments, and need to perform better than those rather than just better than nothing.

Dadface

Interesting stuff.Thank you everyone for your answers.