As with anorexia nervosa, the symptoms of bulimia nervosa might appear in a number of other physical and psychiatric conditions.

Take, for example, the problem of overeating, technically known as hyperphagia. The urge to consume excessive quantities of food can arise when the hypothalamus becomes damaged due to a head injury, tumor, or some other cause.
Endocrine disorders, such as diabetes or hyperthyroidism, can disrupt metabolism, causing the patient to burn energy at an abnormally high rate. When energy stores are depleted, the body, in a kind of metabolic panic, turns on the hunger drive to compensate.

Prescribed medications and illicit drugs also affect eating behavior. Some antidepressants and antipsychotic medications may increase appetite and lead to weight gain. Marijuana is a well-known cause of binge eating. In some patients, frequent abuse of marijuana contributes heavily to the bulimic cycle.

The congenital defect known as Prader-Willi syndrome causes ravenous appetite with poor ability to feel full; the eating thus continues unabated and leads to massive obesity. Abnormal eating occurs in the Kleine-Levin syndrome, which is also marked by periods of extreme sleepiness.

In most of these cases, it’s easy to spot the cause of overeating. Sometimes, though, the cause is more subtle. One of my patients, a sixteen-year-old named Sarah, suffered from a form of epilepsy that produced certain kinds of brain seizures. Two years before, she had started dieting to become thin. She developed anorexia and later became bulimic as well. During a seizure she flew into a rage at any object that happened to be in sight at that moment-a lipstick container, a telephone, whatever.

Sometimes the focus of her rage was the food on her plate. Because food enraged her so much, she stopped eating, eventually losing so much weight that she had to be hospitalized. Specialized brain-wave recordings revealed that her seizures occurred in the part of the brain that controls emotional states, rather than in the part responsible for muscle activity. In Sarah’s case, an anticonvulsant drug played a vital part in treating her eating disorder.

As in anorexia, the distorted attitudes and bizarre behavior caused by bulimia may be confused with other psychiatric illnesses such as schizophrenia. In rare cases, a patient may indeed have both an eating disorder and schizophrenia. Recognizing the presence of both conditions is crucial, since therapy designed to correct one problem may have no effect-or an adverse effect- on the other.