The placebo effect is a measurable change in physiological state or behavior produced by the expectation of therapeutic benefit, independent of any active ingredient in the intervention. Parameters: (1) the administered treatment contains no pharmacologically active component for the condition being treated; (2) the subject holds a belief that the treatment is active; (3) the observed effect is quantifiable — pain reduction, hormonal change, motor improvement, or symptom report. Persistence mechanism: the effect is sustained through repeated clinical documentation, standardized trial protocols (double-blind placebo-controlled designs), and transmission via medical education and research literature. The construct exists as a controlled variable in experimental design and as a named phenomenon in the medical literature. [formal: effectus placebo | substrate: mind | horizon: a moment | explicit: yes | epoch: 0.01]
Accepted ontology entry
placebo-effect
The placebo effect is a measurable change in physiological state or behavior produced by the expectation of therapeutic benefit, independent of any active ingredient in the intervention. Parameters: (1) the administered treatment contains…
Definition
Why it is in scope
A psychological phenomenon where the belief in a treatment's efficacy produces measurable physiological or behavioral effects, even when the treatment is pharmacologically inert. Filed as the named construct used to control expectation in clinical trials — the map of the effect, not any natural biological response.
Names and aliases
- placebo-effecten · CANONICAL
Relations from this entry
- cmrhz9rsf02sj8aehlj6dd3jnDEPENDS_ON →
The placebo effect's mechanism is expectation-driven: a patient's belief in treatment efficacy produces physiological change. Removal test — remove expectation and the placebo effect stops operating entirely. The effect cannot function without the patient's expectation of benefit.
- cmreni1le00twg8vusqrsdf83DEPENDS_ON →
The placebo effect operates through the mechanism of belief: a patient's belief in treatment efficacy drives the physiological change. Remove belief and the placebo effect ceases to function — it has no mechanism independent of belief/expectation. The removal test confirms dependency.
- cmredrvkw0019g8vu7t58pfa8DERIVED_FROM →
The placebo effect was discovered in clinical medicine and emerged from medical research on drug trials. Medicine existed centuries before the placebo effect was catalogued as a distinct phenomenon. Historical dependency confirmed.
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Record identity
- Created
- Aug 5, 2026, 9:50 PM UTC
- Content hash
- d1f42dda4e9c70b5c5860c5db7e65149d2f2f4c1bc54c04586abd0f97739f7ca