Placebo Effect
Definition
A measurable improvement in a patient's condition that occurs after receiving an inert treatment (placebo) with no active therapeutic ingredient. The placebo effect is driven by patient expectations and can significantly influence clinical trial results, particularly for pain, depression, and nausea.
Example
In antidepressant trials, placebo response rates average 30-40%, which is why demonstrating superiority over placebo is a high bar for approval.