We all know of the placebo effect – where a sugar pill improves symptoms or has healing effects. Often said to be “all in the mind” – which it isn’t by the way. Taking a placebo and believing it will work, has physiological effects from changing the way neurons fire (pain relief), change your blood pressure, and can cause warts to disappear. It’s not just a psychological thing, it has physical implications too.
What’s less well-known is the nocebo effect. The dark side of placebo. This again comes from clinical drug trails, where rather than sugar pills having a beneficial effect, the mere mention of side-effects leads them to manifest in physical form. The nocebo effect isn’t random, it occurs when, for example, someone is told a drug has nausea as a side-effect, and even though they’ve been given a sugar pill they soon start to experience nausea, because they’re expecting it.