The 'placebo effect' is a well-known but little-understood aspect of medicine. It occurs when a patient feels better after having a dummy treatment (such as a sugar pill). But experts don't know exactly why placebos work and how they might be used in everyday medicine.
Researchers have now done a large review of the studies on placebos to learn more.
What do we know already?
Placebos come in many shapes and forms, but all are treatments that shouldn't have any specific effect on a patient's illness. They can be inert substances (such as sugar pills or saline injections) or sham procedures that mimic treatments being tested (such as fake acupuncture with toothpicks that don't penetrate the skin).
Doctors also occasionally use 'active' placebos, such as vitamins, painkillers, or other medicines. Although these placebos aren't inert, they shouldn't have a direct effect on the illness being treated (for example, using a vitamin to treat insomnia).
A doctor might prescribe a placebo if regular treatments haven't worked or if a patient has a condition that lacks good medical options. The hope is that the patient will feel better if they take something. However, placebos aren't widely used. This is because experts don't fully understand how they work and what role they should play in medicine. Also, their effect seems largely based on deceiving patients, which raises ethical red flags.
The new review of studies provides some insight.