Anorexia nervosa is not only a psychiatric disorder but a genetic one too, according to a new study published in Nature Genetics and led by researchers at UNC-Chapel Hill and King’s College in London.
The study suggests that genetic factors allow people with anorexia to restrict their eating for longer periods than people who don’t have them. The research discovered that there are eight genetic markers that are associated with anorexia nervosa, possibly explaining why people with anorexia have low body mass indexes.
“We know that people prone to anorexia nervosa can lose dangerous amounts of weight and stay at dangerously low weights,” Cynthia Bulik, a co-author of the study and founding director of the UNC Center of Excellence for Eating Disorders, told the INDY Tuesday. “We know that even after we renourish them, something in their body pulls them back to these really low weights. But we haven’t had the biological evidence to say there’s something metabolic going on here and it’s not just extreme willpower, and that’s really important for patients and families. It helps them understand why it’s so hard to recover from this illness and that there’s something more to it than just the psychological component.”
Anorexia nervosa has always been difficult to treat because its causes have been widely unknown; there is no medication, and relapses are common. Prior research has suggested that the disorder was linked to biology and life circumstances, and thus everyone has a different experience with the disorder, even though there is only one treatment option: nutrition therapy and psychotherapy.
This study might change that by allowing geneticists to develop medications that target the biology of the disorder to identify more personalized treatments.
Between 0.9 and 4 percent of women and about 0.3 percent of men have anorexia. The disorder has the highest mortality rate of any psychiatric illness, and only 20 to 30 percent of patients recover after treatment.
This study also challenges the misconception that anorexia nervosa is mostly sociocultural, which Bulik says has “put us back decades in terms of our research, and it has damaged patients, it has damaged families, and it has done a huge disservice to our patients who really deserve better from the medical field.”
The researchers conducted the study across 100 institutions globally, using 16,992 participants with anorexia and 55,525 control participants. However, the data includes only people of European ancestry across North America, Europe, and Australasia. This is a weakness of the study, Bulik admits.
Further research will explore whether these genetic factors are present in people of Asian, African, and South American descent—digging deeper into what the metabolic component is and how it increases the risk for the disorder, while also expanding the research to people with other eating disorders, such as bulimia and binge eating disorder.
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