A joint study by King's College London and the University of North Carolina reveals that anorexia nervosa is partly a metabolic and not just a psychological disorder 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 as many as 100 academics around the world has identified 8 genetic variants linked to anorexia, a serious and life-threatening disorder.
Anorexia nervosa is a very serious and potentially lethal disorder. Symptoms can include dangerous weight loss, a strong fear of gaining weight, and a distorted perception of one's body.
Anorexia nervosa affects about 1-2% of women and about 0.2-0.4% of men. It has the highest death 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 the metabolic ones (including glycemia), and anthropometric ones, and the study shows how these genetic bases are independent from those that influence the BMI, the body mass index. These factors instead influence the propensity to 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 King's College London's Institute of Psychiatry, Psychology and Neuroscience led the study. Breen states: “The metabolic abnormalities seen in patients with anorexia are often attributed to starvation and fasting. Our study shows that it is not a matter of consequences, but of contributing causes. There genetics plays an important role in this disorder ".
The teacher Janet Treasure, also at King's College London, says: "There is no doubt a concurrence of psychological and metabolic causes, and this evidence may help medicine develop better treatments for this disorder."
Dr Cynthia Bulik, of the University of North Carolina, confirms: "Our findings are an impetus to turn the spotlight on the role of metabolism in anorexia to understand why some patients lose a lot of weight again even under hospital treatment and force-feeding."
Anorexia would therefore be a hybrid, a "Metabo-psychological" disorder, and this enormously modifies both the perception of this disorder and the approach to future better medical treatments.