We've all heard about the placebo effect—how belief in a treatment can trigger real healing responses in the body. But fewer people know about its shadow twin: the nocebo effect, where negative expectations create measurable harm. The word "nocebo" literally means "I will harm" in Latin, and research shows it does exactly that. When patients expect pain, side effects, or poor outcomes, their bodies often comply with frightening precision. The Science of Negative Expectation I