I don't think we dismiss that, but we attribute to the placebo (and nocebo) effect that is very real and still very poorly understood in spite of major efforts

I don't think we dismiss that, but we attribute to the placebo (and nocebo) effect that is very real and still very poorly understood in spite of major efforts in the area. We know it exists, we know the factors that influence it, we know we can't really control it, but we don't understand the mechanism of action.