Meaning
A real or perceived benefit produced by an inert treatment - a sugar pill, sham injection or dummy procedure - arising from the patient's expectation, conditioning or the rituals of care rather than from any active ingredient. Doctors measure it with placebo controls in trials; outside medicine the phrase is used loosely for any improvement that comes from believing in a thing rather than from the thing itself. In clinical trials placebo names the control arm; the effect is strongest for subjective outcomes such as pain and fatigue. Avoid using the phrase to dismiss any benefit a skeptic cannot explain. The nocebo effect is its negative counterpart. Regional use: International English; coined in medical writing, now universal.
Origin
Latin placebo means I shall please. It opened the first antiphon of Vespers in the Office of the Dead - Vulgate Psalm 116:9, Placebo Domino in regione vivorum - and named the rite itself: the OED's factsheet gives earliest English evidence from around 1225, in the Ancrene Riwle. Chaucer turned the word on flatterers: the Manciple's Tale says courtiers sing placebo to please lords, and the Merchant's Tale names a flattering counsellor Placebo. Etymonline, verified on its archived entry, records the medical sense by 1785 - a medicine given more to please than to benefit the patient - and the compound placebo effect from 1900, while the OED's factsheet for the compound gives 1902, in the Sanitarian, with T. C. Graves defining it in The Lancet in 1920. Henry K. Beecher's 1955 JAMA paper The Powerful Placebo popularized the term - Wikipedia's claim that it was the first to use the term is contradicted by the 1900-1902 record, and a 1997 re-analysis by Kienle and Kiene found no evidence of any placebo effect in his data.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- placebo response
- the nocebo effect
Usage Examples
- The improvement in her headaches was probably the placebo effect - the capsule was only starch.
- The app's fans swear by it, but much of the benefit may be the placebo effect of paying for something.
- The nurse bet on the placebo effect, and his pain eased even though the prescription was a dummy.