Researchers believe that anorexia nervosa may have a genetic component, based on results from family and twin studies. People with anorexia nervosa often experience clinically significant anxiety, obsessive-compulsive symptoms, and depression. Reported to regulate mood, satiety, appetite, and behavioral overcontrol, the neurotransmitter serotonin may mediate many of the symptoms of anorexia nervosa. Selective serotonin reuptake inhibitor agents are effective treatment for some eating disorders.

Serotonin activity in the brain has been studied with imaging techniques such as positron emission tomagraphy. This technique is used to localize areas of the brain responsible for appetite, satiety, and impulse control, and to investigate a particular serotonin receptor, 5H2a, in the brain. Those studies have reported distinct and persistent differences in the brains of people who have recovered from anorexia nervosa. Additional changes observed after recovery from anorexia nervosa include elevated spinal fluid concentrations of 5-HIAA, the major metabolite of serotonin, and altered behavioral responses to administration of serotonergic agents.

Genetic factors contributing to anorexia nervosa have been studied using linkage analysis in pairs and trios of relatives of persons with anorexia nervosa. The results indicate 63% of the pro-band-relative pairs were anorexia-anorexia, 20% were anorexia-bulimia and 16% were anorexia alone.

Dr. Kaye explained that these studies represent the first large-scale molecular genetic investigation of anorexia nervosa. The data obtained from affected probands and relatives will allow investigation of the genetic transmission of eating disorders with a genome scan and assessment of candidate genes. Current research includes investigation of genes related to serotonin synthesis and those involving serotonin receptors.