For many years, Bulik says, AN was thought of primarily as a disorder of the mind with no physical basis. Symptoms like extreme thinness, a high activity level, and obsessive traits were all thought to be psychological and related to a single disease. But “what I saw clinically didn’t jive with what I read in the literature,” she says. Widespread theories about AN that she encountered early in her career—for example, that male patients couldn’t have it—also didn’t make sense with what she saw in practice. People of all genders can have anorexia nervosa, which isn’t adequately addressed by current literature.