You’re probably aware of the placebo effect—because you think it’s real medication, a sugar pill, for example, relieves your pain—but have you heard of its evil twin, the nocebo effect?
Through different biological mechanisms, it achieves something very similar to the placebo effect, but reversed: If you’re told your sugar pill causes side effects like nausea or rashes, you might very well experience them.
Read The Scientist‘s investigation of the subject for more on how the nocebo effect can cause not only individual health problems but also “have a worrisome effect on” the use of vaccines and other widespread treatments.
