Studies of heart patients who had surgeries and were prayed for with the prayer, "May they have successfull surgeries and with no complications" indicated that they all had successfull surgeries but that the number of complications increased substantially, perhaps because, on an unconscious level, our minds do not perceive the word "no"... That explains why when you tell someone, "Don't think of purple elephants or don't walk on the grass", you find them doing it when they might not have thought of doing it prior to your prohibition. Keep your affirmations, your prescriptions for healing and your directions to adults and children in the positive... You will see more positive effects.