Nocebo
Etymology
From Latin nocebo, "I shall harm," from nocere, "to harm" (the same root as "innocent" and "noxious"). It was coined in the 1960s as a deliberate opposite to placebo, keeping the same grammar but flipping the meaning. It names the finding that expecting harm — from a scary diagnosis, an ominous warning, or a distrusted drug — can itself trigger real discomfort.
noun · /noh-SEE-boh/
A harmless treatment or warning that produces real negative symptoms because the person expects to be harmed.
What it names
Why reading a long list of possible side effects can sometimes give you those very symptoms — dread has physical consequences.
Example
After the news story on side effects, so many patients reported nausea that doctors suspected a nocebo effect.
Related idea
Placebo is benefit from positive expectation; nocebo is symptoms from negative expectation.