Rowling’s mother, who had multiple sclerosis, died in 1990, after which Rowling suffered a period of depression. She would use the experience to characterize the Harry Potter’s dementors, creepy creatures that feed on human emotion. “It's so difficult to describe [depression] to someone who's never been there, because it's not sadness," Rowling told Oprah Winfrey. “I know sadness. Sadness is to cry and to feel. But it's that cold absence of feeling—that really hollowed-out feeling. That's what Dementors are.”