How does mrs Breedloves treatment of Pecola contribute to her ugliness

Mrs. Breedlove is ceuel and abusive to Pecola. She constantly tells her that she is ugly. Terrified of her parents, she is not free (due to gender and age) to run away from home as Sammy does. Either during the pregnancy or after the miscarriage, Pecola goes mad, manufacturing an imaginary friend who becomes her only conversation partner.