In Harry Potter and the Prisoner of Azkaban, after Harry explained the boggart would change into a dementor for him, Lupin says, "That suggests that what you fear most of all, is fear itself. This is very wise."
Franklin Delano Roosevelt famously said in his first inaugural address (1933), "The only thing we have to fear is fear itself".
Is there a reason for this similarity? Or is it purely coincidental?