What is a Placebo?
A double-blind trial is the standard method for deciding whether or not a treatment has any “real” effect. A placebo is a “treatment” that has no effect except through the mind of the patient. The usual form is a pill containing a little lactose (milk-sugar), although a bitter-tasting liquid or injections of 1cc saline can be used instead. The “placebo effect” is the observed tendency for patients to display the symptoms they are told to expect. The problem is that the state of mind of a patient is often a significant factor in the effect of a course of treatment. All doctors know this; it is why “bedside manner” is considered so important. In statistical tests of new treatments it is even more important, since even a small effect from the state of mind of a small fraction of the patients in the trial can have a significant effect on the results. Hence new medicines are tested against a placebo. The patients in the trial are randomly divided into two groups.
A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment’s effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or treatment.
