A major international collaborative study involving Canadian researchers has found that anorexia may be at least partly explained as a metabolic disorder, not exclusively a psychiatric one.
Anorexia nervosa is characterized by restrictive eating habits, fears of weight gain, unhealthy weight loss, and a distorted view of one’s body image. Between 1-2% of women and 0.2-0.4% of men are thought to be affected. The condition has the highest fatality rate of all psychiatric disorders, yet patients continue to suffer stigmatization including misguided accusations of living out a ‘lifestyle choice’.
Due to the dual effect of anorexia on the mind and body, a firm definition has long been elusive, but this research may help to uncover its true diagnostic identity.
“Over time there has been uncertainty about the framing of anorexia nervosa because of the mixture of physical and psychiatric features,” says co-author Janet Treasure. “Our results confirm this duality and suggest that integrating metabolic information may help clinicians to develop better ways to treat eating disorders.”
Data sourced from approximately 17,000 people in 17 countries were analyzed by a team of over 100 scientists. Around 55,000 other people’s data sets were used for control purposes. Every subject’s DNA was analyzed to look for genetic mutations common to anorexia sufferers.
The team discovered that eight metabolic genetic variants which influence things like physical activity and fat burning could have a direct connection to anorexia. Perhaps unsurprisingly, they also overlap with other mental disorders like depression, anxiety, OCD, and schizophrenia.
The researchers suspect that the variants could overturn signals from the body that would normally stimulate hunger during states of extreme weight loss or starvation. Sufferers are thus able to starve themselves for longer than the average person.
“Metabolic abnormalities seen in patients with anorexia nervosa are most often attributed to starvation, but our study shows metabolic differences may also contribute to the development of the disorder,” says Gerome Breen, co-lead on the new study. “Furthermore, our analyses indicate that the metabolic factors may play nearly or just as strong a role as purely psychiatric effects.”
Although this study is the largest of its kind, team members on the study have commented that many more genetic variants involved in anorexia likely await discovery.
The researchers are looking to expand their future efforts by incorporating up to 100,000 anorexia patients internationally and also exploring other eating disorders like bulimia and overeating. More immediately, the authors suggest that clinicians should reconsider the condition as a “metabo-psychiatric disorder”.
“This is ground-breaking research that significantly increases our understanding of the genetic origins of this serious illness,” commented Andrew Radford, from Beat — a UK eating disorder charity. “We strongly encourage researchers to examine the results of this study and consider how it can contribute to the development of new treatments so we can end the pain and suffering of eating disorders.”