I just finished reading one of the many "brain books" that have recently been written on the subject of aging brains and how to keep them as functional as possible. (Of course the definitive answer is: you must give it lots of exercise.) I view everything through the prism of PD because that's where I'm coming from. The Placebo effect is believed to be powerful because of the belief we have that we are the beneficiary of something that will help us.
There is not much doubt left in the minds of even the most hardened scientific thinker that our brains and the abstract but detectable operation of the effect of what we think about has the power to change things on a physiological level. Thus we have hard science come face to face with religion.

The placebo effect must be the positive side of a two sided coin. If what we believe can produce the placebo effect, its flip side must be capable of much havoc. Religion, for the most part, pushes us to have faith, hope and to believe in something much bigger than ourselves. For those that possess this intangible diamond or even only some small portion, it lightens the load. "Religion" is just a word. You can call it spirituality, belief in a higher power or whatever you want to call it, but it is real and powerful and that is why it is a benefit.