Atheists, and all non believing alike, If Faith is nonexistent then how do you explain the placebo effect?

Placebo effect: Also called the placebo response. A remarkable phenomenon in which a placebo -- a fake treatment, an inactive substance like sugar, distilled water, or saline solution -- can sometimes improve a patient's condition simply because the person has the expectation that it will be helpful. Expectation to plays a potent role in the placebo effect. The more a person believes they are going to benefit from a treatment, the more likely it is that they will experience a benefit.