You have heard of the placebo response and have a general idea of how it works. The reality is that few of us know just how powerful it is.
This wouldn’t be a problem except that most drugs, when studied in clinical trials, are compared to placebo. This means that patient beliefs during treatment may have much stronger effects than the drug itself. Many drugs are studied under double-blind placebo controlled studies in the attempt to control for the placebo response. In these studies, neither the reviewer (many times this is the treating physician) nor the patient knows who is taking the placebo and who is taking the active drug. But if the patient even thinks he or she is on the active drug, it can completely throw off the results of the study.