When there is no serious harm, it is generally considered ethical to ask patients to participate in a placebo-controlled trial, even if they may experience discomfort as a result, provided the setting is noncoercive and patients are fully informed about available therapies and the consequences of delaying treatment.
A placebo-controlled trial is a type of clinical trial or research study in which a placebo is used. Carefully conducted clinical trials are used by scientists to find out whether a new treatment works or not.
A placebo-controlled trial can be done in any phase, but is usually done in Phase 2 or 3.
Why Use Placebos?
People may wonder why placebos are used at all. The main reason is to account for the fact that when people improve in a clinical trial, it can be due to reasons other than the experimental treatment. People can improve in a trial because of:
· Spontaneous recovery (they would have gotten better anyway)
· A “clinical trial effect” (or improvement from all the extra care and attention participants receive in a trial) or
· The “placebo effect” (something like the power of positive thinking, or the tendency for trial participants to improve when they believe they have been given an effective treatment).
In this sense, experimental drugs are like “placebo with value added.” The principle behind placebo use is to have two groups where everything is the same except for the drug. Thus, one can conclude that any difference between the two groups is due to the drug effect.
Placebos are also useful in identifying side effects. If two treatments are compared, they may have similarly high side effects. Placebos provide a “blank slate” by which to assess the adverse effects of experimental treatments. On the other hand, a PCT cannot provide the information to determine if the experimental treatment is better than the proven treatment.
When are Placebos Not Used?
There is agreement that PCTs are not conducted if there is any risk of irreversible harm to participants. For example, cancer patients would not be taken off chemotherapy or radiation therapy and people suffering from AIDS would not be asked to stop their treatment for the purpose of testing new drugs. Likewise, a depressed person who was suicidal would not be allowed to participate in a placebo-controlled trial.