Originally Posted by omnimirage the II
Somebody mentioned that if a effect produced from a action was placebo derived, that over time the effect will lose it's magnitude to the point it becomes non-existent;
This is definitely not true in some cases. There are all kinds of BS homeopathic and neutraceutical products out there that do nothing and yet people take them day after day convinced that they help.
For example, products that claim they prevent you from getting a cold, or even if a cold breaks through it won't be as bad or last as long. As colds are variable and self-limited, every day is a confirmation of the placebo, literally no matter what happens.