For hundreds of years, the medical community has known that the mere act of receiving treatment, even if it’s just a sugar pill, can improve a patient’s symptoms. Therefore, in order to ensure that the effects of an experimental treatment are real, most randomized controlled trials (RCTs) include a placebo arm.
Placebos are most often pharmacologically inactive pills that mimic the physical characteristics of the study drug, but they can also take the form of inert medical devices, sham surgeries, and fake acupuncture. The placebo effect is broader than just patient improvement in response to this inactive treatment; it encompasses the patient’s response to the entire therapeutic context in which treatment is administered.
There is actually not one single placebo effect – but many – all of which come together to produce symptom improvement through mind-brain responses to treatment context. Psychosocial factors such as expecting to get better, rituals of care, active engagement in treatment, and even the mere act of taking a pill can all contribute to the placebo response. Research has also shown that how the placebo is administered is just as important as what is administered. The type of placebo, the color and dosing regimen of pills, and how caring the physician acts can all influence the magnitude of the response.