June 3, 2009 Jeanne Rust

Are Eating Disorders Hereditary?

One of the questions that seems to arise again and again is, "My aunt and my mother had an eating disorder.

  • Is it hereditary?
  • Am I at risk?

The high incidence of eating disorders in families has led researchers to think that there might be a genetic influence in the development of them. Studies have shown that 58% to 76% of the occurrence of anorexia nervosa can be attributed to genetic factors.

The prevalence rate of anorexia nervosa in sisters of patients is estimated at 6%. Most of our genetic evidence in the development of anorexia nervosa comes from twin studies, in which the twins are raised apart.

These studies reported substantially higher rates for the development of anorexia in monozygotic twins than for dizygotic twin pairs While recent data suggest that there is some kind of genetic aspect to the development of anorexia, conclusive data for genetic transmission are not yet available. The National Institute of Mental Health is funding a five-year study, with more than $10 million in funding, which brings together 11 groups of researchers from North America and Europe (10 clinical centers and one to analyze data) to discover the genes that influence risk for anorexia.

In 2000, researchers identified shared genetic susceptibilities to major depression, substance abuse, anxiety disorders and personality disorders. Similarly, there is growing evidence to suggest that anorexia nervosa as well as bulimia nervosa likely share the same genetic risk factors. Family and twin studies indicate that relatives are at increased risk for anorexia and bulimia because of a hereditary component between the two disorders.

A high probability also exists that there is a genetic predisposition to obesity and binge-eating disorder.

An additional question is

  • Can I become cured from an eating disorder?
  • Will I have to live with this forever?

The answer is "yes" and "no".

A person can become completely well or cured and it requires a tremendous amount of hard work.

Outcome studies on anorexia nervosa have been available in the literature for at least four decades, from the 1950s.

In 1995, researchers published a review of 68 outcome studies published between 1953 and 1989 concerning a total of 3,104 patients. The follow-up results show a large variation in the main features of anorexia - weight, menstruation, and eating behavior.

They found the following:

In close to 60% of anorexics, weight and menstruation may normalize, whereas somewhat fewer (49%) show normalized eating behavior. The distinction between recovery, improvement, and chronicity (which to a great extent is based on a popular but crude differentiation between good fair, and poor outcome) shows that, on the average, more than 40% of anorexics recover, one-third improve, and 20% have a chronic course.

Another study was published that was a 10-year follow-up study of 76 severely ill females with anorexia nervosa. Five patients had died, which showed a mortality rate of 6.6%. Only 18 (23.7%) were fully recovered after 10-years. Sixty four per cent developed binge-eating at some time during the course of their illness, 57% at least weekly. A little over 25% of the patients studied had a good outcome as they were able to re-establish normal weight and regular menstrual cycles, even though they still were not eating normally.

They used a variety of anorexic-type behaviors to control their weight and showed significant body image disturbance.

Forty-five percent were unable to establish normal weight and menstrual cycles, nor to normalize other anorexic symptoms.

When we take a look at the research that has been done on eating disorders, we see that they might be genetic in origin and we also see how serious they truly are!