MODEL RELEASED. Placebo drug trial. Conceptual image of a blindfolded woman facing a choice between three sets of drug capsules, one of which is a placebo. This image represents a type of clinical drug trial known as a placebo-controlled study. Some of the patients receive a placebo in the form of capsules containing no drugs. They do not know whether they are receiving the drug or placebo, so this is a form of blind study. This is intended to allow the medical researchers evaluating the new drug to take into account the placebo effect, where patients improve due to the belief that they are being treated, even if no drug if administered.