Anorexia Nervosa Classification Research

Cynthia M. Bulik, Ph.D., FAED

UNC Department of Psychiatry

Distinguished Professor of Eating Disorders, Department of Psychiatry
Professor of Nutrition, Gillings School of Global Public Health
Founding Director, UNC Center of Excellence for Eating Disorders
Co-Director, UNC Center for Psychiatric Genomics

Using advanced data analytic approaches, Dr. Bulik and her team demonstrated that individuals with anorexia show strong genetic correlations not only with other psychiatric disorders (i.e. obsessive-compulsive disorder, depression, anxiety disorders), but also very strong negative genetic correlations with body mass index, body fat percentage, and other metabolic traits such as fasting, insulin, leptin, and type 2 diabetes. These novel observations encouraged the team to rewrite the book on anorexia nervosa and to reconceptualize the illness as both a psychiatric and metabolic disorder.

Advanced data analytic approaches allow the team to conduct genetic correlations across traits. Essentially, this means that on a genetic level, the team can determine the extent to which two or more disorders are related. For example, you can say that two disorders (such as schizophrenia and bipolar disorder) are highly genetically correlated (i.e. same genes contribute to risk) and the risk conferred is in the same direction (same genes increase risk in both cases). Dr. Bulik’s area of interest is eating disorders, specifically the genetics of anorexia nervosa. Until now, anorexia nervosa has been considered to be primarily a psychiatric disorder. Unfortunately, research has not yet identified effective treatments that keep people well in the long term. When Dr. Bulik applied this genetic correlation approach to a large sample of individuals with anorexia nervosa (partially funded by the Foundation of Hope), she saw not only strong genetic correlations with other psychiatric disorders (i.e. obsessive-compulsive disorder, depression, anxiety disorders), but also very strong negative genetic correlations with body mass index, body fat percentage, and other metabolic traits such as fasting insulin, leptin, and type 2 diabetes. This means that some of the same genes that influence these metabolic traits also influence risk for anorexia nervosa, but they are acting in opposite directions. For example, genetic risk for low body mass index or type 2 diabetes is associated with increased risk for anorexia nervosa. These novel observations encouraged Dr. Bulik and her team to rewrite the book on anorexia nervosa and to reconceptualize the illness as both a psychiatric and metabolic disorder. Their next steps are to figure out exactly how these metabolic factors influence risk with the hope that attending to both psychiatric and metabolic factors will allow them to improve outcomes for this frequently fatal condition. The Foundation of Hope is also supporting Dr. Bulik’s efforts to expand her work to other eating disorders including bulimia nervosa and binge-eating disorder.