Placebo effect is where the drug causes greater effect and thereby faith accentuates, prolongs and promulgates the strength of the drug. Faith in an object that is known creates a strength in the object's reaction in a more powerful manner, provided the object was intended to create positive in the first place. Yet if this faith is turned inward in a negative manner, it can hinder the effectiveness of the drug or creative power of the thing being used for the positive, this is called the nocebo effect.
We often give painkillers the credit that ought to be given to the passage of time, the belief that they would kill the pain, or the water that accompanied them.