Researchers say that genetic factors and neuroticism may be linked with anorexia nervosa.
Anorexia nervosa is the exaggerated fear of weight gain that causes many young women to starve themselves sometimes to death; it has one of the highest death rates of any mental disorder.
In a large study using the Swedish Twin Registry, the researchers examined the prevalence, heritability and risk factors for anorexia; they found that anorexia nervosa was moderately heritable and linked to neurotic behavior early in life among women.
The study says that more than 50% of the risk for developing the eating disorder is based on family history.
According to Cynthia M. Bulik, Ph.D., of the University of North Carolina at Chapel Hill and colleagues, other unspecified factors such as environmental factors, triggered the disorder in 44 percent of the cases.
The disorder causes victims to have an extreme fear of obesity and an aversion to food, but despite the seriousness of anorexia, little is known about risk factors for its development.
In a previous study it was found that the number of new cases of anorexia increased during the past century and leveled off in the 1970s.
In 2002 anorexia was seen in 1.2 percent of women and .29 percent of men.
Using information from questionnaires given in 1972 and 1973, the researchers examined seven potential predictors of anorexia among women:
- Body Mass Index (BMI),
- stomach problems,
- excessive exercise,
- perceived stress,
- an extroverted personality and neuroticism, characterized by low self-esteem,
- emotional instability
- and feelings of depression, anxiety and guilt.
Of these, only neuroticism was identified as a risk factor for subsequent anorexia.
The researchers estimate that the disorder is 56 percent heritable, with the remaining differences caused by environmental factors.
The report was published in the Archives of General Psychiatry.