A joint study by King's College London and the University of North Carolina reveals that anorexia nervosa is partly a metabolic disorder and not just a psychological one as previously believed.
The research was published in the latest issue of the journal Nature Genetics.
THEgenomic analysis on a large scale carried out by 100 academics around the world has identified 8 genetic variants linked to anorexia, a serious and potentially lethal disorder.
Anorexia nervosa is a very serious and potentially lethal disorder. Symptoms can include a dangerous drop in body weight, a strong fear of gaining weight and a distorted perception of one's body.
Anorexia nervosa affects approximately 1-2% of women and approximately 0.2-0.4% of men. It has the highest mortality rate among psyche-related disorders.
The researchers combined data collected by the Anorexia Nervosa Genetics Initiative and the Psychiatric Genomics Consortium's Working Group on Eating Disorders. The resulting database included 16.992 cases of anorexia and 55.525 controls from 17 countries in North America, Europe, Asia and Australia.
The key findings of the study
The genetic bases of anorexia have been crossed with metabolic (including glycemia) and anthropometric ones, and the study shows how these genetic bases are independent from those that influence BMI, the body mass index. These factors instead influence the propensity for physical activity, which is particularly high in subjects with anorexia.
Dr Gerome Breen of the National Institute for Health Research (NIHR) and a team from the Institute of Psychiatry, Psychology and Neuroscience at King's College London conducted the study. Breen states: “Metabolic abnormalities observed in patients with anorexia are often attributed to starvation and fasting. Our study shows that these are not consequences, but contributory causes. There genetics plays an important role in this disorder.”
The teacher Janet Treasure, also at King's College London, says: “There is undoubtedly a combination of psychological and metabolic causes, and this evidence could help medicine develop better treatments for this disorder.”
Dr. Cynthia Bulik, from the University of North Carolina, confirms: “Our findings are an impetus to shine a spotlight on the role of metabolism in anorexia to understand why some patients lose a lot of weight again even under hospital care and force-feeding.”
The conclusions
Anorexia would therefore be a hybrid, a "Metabo-psychological" disorder, and this enormously modifies both the perception of this disorder and the approach to better future medical treatments.
