Nocebo

Both nocebo and placebo effects are presumably psychogenic.

The nocebo effect is the opposite of the placebo effect.

In fact, it is even possible for a patient’s response to a drug product to vary based on changes in the physical attributes of the drug, referred to as the placebo or nocebo effects.

It is somewhat surprising that little attention has been drawn to the existence of the contrary effect [to the placebo] – which I may call the nocebo reaction.

In the case of the nocebo, it is negative expectations that become self-fulfilling prophecies.

It seems to be a "nocebo" effect – the self-diagnosed gluten sensitive patients expected to feel worse on the study diets, so they did.

If there's one lesson to be drawn from the nocebo effect, it's that ideas are never merely ideas. […] Maybe you see where I'm going with this: our grim view of humanity is also a nocebo.