1.   But what defines any psychiatric disorder is the combination of symptoms and how long they last, not one particular symptom.

2.   According to the National Institute of Mental Health, an obsessive-compulsive disorder is defined by repeated, unwanted thoughts or compulsive behaviors that seem impossible to stop or control.

3.   No studies have pinpointed exactly how prevalent disordered eating is among female athletes, mainly because of disagreement about how to define the disorder.

4.   The disorder was defined by James Parkinson, a British surgeon.