Mindfulness meditation has a measurable and significant effect not only on stress, emotional regulation, recurrent thoughts/rumination, attention, and decision-making, but also a physical effect in the brain in the form of a reduction of amygdala size, and an increase in the activity (and size) of the prefrontal and anterior cingulate cortices.
`Internally', it changes the meditator's subjective sense of self and of how he experiences the world.
If the placebo effect can be demonstrated to having positive effects in pain killing, and healing, it should be studied with enthusiasm.
We all know how stress can have negative effects on health. Why should the placebo effect and "positive thinking" not be able to have positive effects on health?
http://www.sciencedaily.com/releases/2010/08/100816155000.ht...
You're learning to choose a new primary neural pathway that tends to route around the fight/flight parts of the brain and route into lesser understood parts of the brain. The end effect is a calmer, happier, less worried you, but it takes.. well... practice :)