Traditionally, eating disorders have primarily been viewed by the medical profession as psychological illnesses. But a new international study involving University of Otago researchers has identified distinct genetic signatures for binge eating and anorexia nervosa, which are now challenging the long-held notion. The findings represent an important shift in how eating disorders are understood and potentially treated. Led by researchers at King’s College London and the University of North Carolina, the study is the first to map and directly compare the genetic profiles of binge eating and anorexia nervosa at a large scale. The research, published in the United Kingdom Journal Nature Mental Health, includes genetic data from more than 500 New Zealand study participants, contributed by University of Otago (Christchurch) Faculty of Medicine researchers. University of Otago clinical psychologist Associate Prof Jenny Jordan said the findings challenged the idea that eating disorders could be understood solely through a psychological lens. “Even though these two conditions both fall under the category of eating disorders, they clearly differ deeply on a biological level.” Otago pathology and molecular medicine researcher Prof Martin Kennedy said the study showed clear genetic signatures for binge eating and anorexia nervosa, which provided some of the clearest evidence yet that eating disorders were influenced by both psychiatric and metabolic biology. SuppliedUniversity of Otago (Christchurch) pathology and molecular medicine researcher Prof Martin Kennedy. Photo: Supplied For the first time, researchers identified eight different genomic regions associated with anorexia nervosa; and six genomic regions associated with binge-eating behaviour, including one close to a gene well known for its relationship with body weight. The researchers also found genetic connections between both conditions and other psychiatric disorders like depression and anxiety. Anorexia nervosa displayed a stronger genetic relationship with obsessive-compulsive disorder, and binge eating was strongly associated with attention-deficit/hyperactivity disorder (ADHD). However, the researchers found the genetic contribution to eating disorders could not simply be explained by genes influencing body weight or body mass index. The findings instead supported the concept of eating disorders as “metabo-psychiatric” conditions — illnesses shaped by an interplay of metabolic and psychiatric genetic factors. Assoc Prof Jordan said the findings represented an important shift in how eating disorders were understood and potentially treated. “These results not only help us understand both shared and distinct causes of these eating-related traits, but may also help us develop more precise treatments targeting the specific biology of each condition.” The next phase of the research will draw on approximately 4000 New Zealand participants who have contributed to the Eating Disorder Genetics Initiative (EDGI), further strengthening New Zealand’s contribution to international eating disorder research. Recognising their biological complexity could ultimately help researchers develop targeted approaches to treatment and prevention that were better matched to the underlying biology of individual conditions, she said. john.lewis@odt.co.nz
