One day 12-year-old Elizabeth McIngvale became obsessed with the number 42, which happened to be her mother’s age at the time, 11 years ago. When she washed her hands, she had to turn the sink on and off 42 times, get 42 pumps of soap and rinse her hands 42 times. Sometimes she decided that she actually needed to do 42 sets of 42. When she dressed, she put her right leg in and out of her pant leg 42 times, then the left. Even getting up from a chair took 42 attempts. She was afraid that if she did not follow her self-prescribed ritual, something terrible would happen to her family—they might die in a car accident, for instance. “Everything I did was completely exhausting and grueling,” she recalls. “I was probably doing 12 to 13 hours a day of rituals.”