nocebo

[ noh-see-boh ]
/ noʊˈsi boʊ /

noun

an inactive substance or a real medication that produces unpleasant or worsening symptoms in a patient or research participant because the person expects negative effects.
a negative symptom experienced by a person with such expectations.

Origin of nocebo

1960–65; Latin nocēbō I shall be harmful; patterned after placebo