From “Placebo Effects in Medicine,” by Ted Kaptchuk and Franklin Miller:
So what have we learned about placebo effects to date, and what does our current understanding say about medicine?
First, though placebos may provide relief, they rarely cure […] Second, placebo effects are not just about dummy pills: the effects of symbols and clinician interactions can dramatically enhance the effectiveness of pharmaceuticals. […] Third, the psychosocial factors that promote therapeutic placebo effects also have the potential to cause adverse consequences, known as nocebo effects. […]
Placebo effects are often considered unworthy and illegitimate. They are thought to be unscientific and caused by bias and prejudice. This attitude obscures a core truth of medicine: medicine’s goal is to heal, which can include cure, control of disease, and symptom relief or provision of comfort. […]
Medicine has used placebos as a methodologic tool to challenge, debunk, and discard ineffective and harmful treatments. But placebo effects are another story; they are not bogus. With proper controls for spontaneous remission and regression to the mean, placebo studies use placebos to elucidate and quantify the clinical, psychological, and biologic effects of immersion in a clinical environment.