A placebo is defined as an inactive substance (usually a sugar pill) which resembles a medication, given for psychological effect or used as a control in evaluating a medicine believed to be active. Up to now, much of medicine was built on placebos. They were extensively used for testing and research purposes. Interestingly enough, the idea and use of the placebo is older than its actual existence. In the early decades of the 20th century, most of the medicines prescribed by physicians were later found to have no effect on the illnesses they were prescribed. Nevertheless, the use of these placebos in research became indispensable. Despite the overwhelming evidence that placebos do help improve medical conditions the FDA remains reluctant to approve them for anything more than clinical research. .
But, how do placebos work? Although there are a great many theories on this subject, few answers have been found. Many believe that the response to placebos is one of conditioning. That we are conditioned by society to associate physicians and medicine with good health. And that as a result of this classical conditioning (take medicine-feel better) we react to the presence of the doctor or the act of taking a sugar pill with a strong mental response. Others believe that the fact that the person who has taken a placebo believes they have been cured, the body's stress level has been lowered allowing it to naturally heal itself. Still others believe that biological molecules in the brain help carry out the placebo effect. .
Many physicians discredit placebos because they do not wish to lie to their patients. However it is impossible to prove that doctors aren't lying by putting their faith in accepted treatments because it is impossible to prove that the treatment doesn't rely, even in part, on a placebo effect. It could be that the patients belief in the usefulness of the medicine is what makes it work.