Understanding Eating Disorders

Eating disorders, such as anorexia nervosa, bulimia nervosa, and binge eating, are among the most frustrating and difficult-to-treat conditions anyone can face. Research efforts at several NIH institutes are helping health care professionals and their patients better understand what can be done to deal with these conditions.

Eating disorders can affect girls and boys, women and men, people of all races and backgrounds. But because of the stigma or misperceptions, some people may not get the help they need. Mental health experts say it is important for people to understand what eating disorders are and what they are not. Eating disorders are not a silly desire to be thin, a figment of one's imagination, or a failing.

"The most important thing to recognize is that these are real disorders that require treatment," says Dr. Thomas Insel, the director of the National Institute of Mental Health (NIMH).

Eating disorders are serious, even life-threatening, medical illnesses that have biological and psychological causes. They are treatable. Recovery is possible.

"I tell my patients they are fighting an uphill battle against their biology. That does not mean it is not a fightable battle, because it is," says Cynthia Bulik, Ph.D. director of the eating disorders program at the University of North Carolina at Chapel Hill, which receives NIH funding for research.

What Are Eating Disorders?

Eating disorders are marked by extremes. People with an eating disorder may severely reduce the amount of food they eat, or eat an unusually large amount of food, or be extremely concerned about their weight or shape. They may start out simply eating smaller or larger portions than usual, but at some point the urge to eat more or less spirals out of control.

There are three main types of eating disorders: anorexia nervosa, bulimia nervosa, and binge-eating disorder. People with anorexia nervosa see themselves as overweight even though they are dangerously thin from starving themselves. People with bulimia nervosa eat unusually large amounts of food (binge eat) and then compensate by purging (vomiting, taking laxatives or diuretics), fasting or excessive exercise. People with binge-eating disorder binge but do not purge, and they often become overweight or obese. Eating disorders may occur along with depression, substance abuse, or anxiety disorders, and can cause heart and kidney problems, even death. The disorders show up most frequently during teenage years, but there are indications they may develop earlier or later in life.

Dr. Bulik and others in the field say they have seen an increase in adult women with eating disorders. At any given time, more than half the women in her program are older than 30, which was not the case 10 or 20 years ago, she adds. Dr. Bulik notes that environmental triggers, like the expectation to lose weight quickly after pregnancy, or to look young, can lead to extreme dieting or exercise.

"There are such extraordinary pressures on us not to let age show on our body," she says. "So, we are seeing more women caught up in extreme behaviors, and it's those behaviors that can trigger an eating disorder in a vulnerable individual."

There are clues as to what makes people likely to develop an eating disorder.

"There have been a number of studies showing that people who develop anorexia nervosa have certain traits in childhood that put them at risk, such as anxiety and perfectionism. If people do not have those traits, they are probably less likely to develop an eating disorder," says Walter Kaye, M.D. He directs the eating disorders program at the University of California, San Diego and also receives NIH funding for his research.

Studies also show eating disorders run in families. But is it nature or nurture, inherited or learned behavior? Studies of twins suggest that genes play a role. To help further research into the genetics of eating disorders, Drs. Kaye, Bulik, and other researchers are collecting DNA and blood samples from people in families where more than one person has anorexia nervosa. NIMH is supporting the research and will maintain a bank of the DNA and cell lines collected, so they can be used by researchers trying to identify variations in genes that affect the risk for anorexia and bulimia nervosa.

"By identifying these factors, we could see who is at risk, intervene early, and prevent people from coming into the emergency room," says Dr. Insel.

In addition to studying genes, researchers are using sophisticated imaging tools to see what is, or is not, happening in the brains of people with eating disorders.

"When it comes to hunger, it's hard for most people to stay on a diet. But, people with anorexia nervosa can diet every day and die from starvation. Why don't systems kick in that make them want to eat?" says Dr. Kaye. By uncovering and understanding the differences in the brain circuitry and genes of people with eating disorders, researchers can work to develop new treatments.

Current treatment options may include mental health therapy, nutritional counseling, and medicines. One largescale study suggests an online-intervention program may help some college-aged women who are at high risk of developing an eating disorder. The program includes online discussion groups moderated by psychologists, as well as reading and writing assignments.

Researchers are also studying the effectiveness of "family-based therapy" to treat children and teens with anorexia and bulimia. In family-based therapy, parents play an important and active role in a child's treatment. Additionally, a study is starting to see how this type of approach could be applied to adult couples in which one partner has anorexia nervosa.

Because eating disorders are complex and affect a variety of people in a number of ways, several institutes at NIH are funding research. The National Institute of Mental Health supports the majority of research, but studies also are supported by the National Institute of Diabetes and Digestive and Kidney Diseases, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.