[rmc]

With drugs there is also the placebo effect. This is where people will get better if the 'drug' is thought to be more effective. If you give people 4 sugar pills instead of 2, they feel better faster. This isn't wishy-washy 'feel better' stuff, but an actual improvement. People's brains can influence they bodies.

Real drugs are tested against placebos, and they have to 'beat the placebo' before we call them 'drugs'. (i.e. if they don't beat the placebo, they clearly don't work). And obviously although placebos work, they don't work very well, so you can't 'think yourself free of cancer'.

The placebo effect is one of the current unsolved mysteries of science today.