Neonatal complications may also have an influence on harm avoidance, one of the personality traits associated with the development of AN.Neuroendocrine dysregulation: altered signalling of peptides that facilitate communication between the gut, brain and adipose tissue, such as ghrelin, leptin, neuropeptide Y and orexin, may contribute to the pathogenesis of anorexia nervosa by disrupting regulation of hunger and satiety.Gastrointestinal diseases: people with gastrointestinal disorders may be more at risk of developing disorders of eating practices than the general population, principally restrictive eating disturbances. An association of anorexia nervosa with celiac disease has been found. The role that gastrointestinal symptoms play in the development of eating disorders seems rather complex. Some authors report that unresolved symptoms prior to gastrointestinal disease diagnosis may create a food aversion in these persons, causing alterations to their eating patterns. Other authors report that greater symptoms throughout their diagnosis led to greater risk. It has been documented that some people with celiac disease, irritable bowel syndrome or inflammatory bowel disease who are not conscious about the importance of strictly following their diet, choose to consume their trigger foods to promote weight loss. On the other hand, individuals with good dietary management may develop anxiety, food aversion and eating disorders because of concerns around cross contamination of their foods.
In extreme cases, patients with anorexia nervosa who continually refuse significant dietary intake and weight restoration interventions, and are declared incompetent to make decisions by a psychiatrist, may be fed by force under restraint via nasogastric tube after asking their parents or proxies to make the decision for them.The cause of anorexia is currently unknown. There appear to be some genetic components with identical twins more often affected than fraternal twins. Cultural factors also appear to play a role, with societies that value thinness having higher rates of the disease. Additionally, it occurs more commonly among those involved in activities that value thinness, such as high-level athletics, modeling, and dancing. Anorexia often begins following a major life-change or stress-inducing event. The diagnosis requires a significantly low weight and the severity of disease is based on body mass index (BMI) in adults with mild disease having a BMI of greater than 17, moderate a BMI of 16 to 17, severe a BMI of 15 to 16, and extreme a BMI less than 15. In children, a BMI for age percentile of less than the 5th percentile is often used.Treatment of anorexia involves restoring the patient back to a healthy weight, treating their underlying psychological problems, and addressing behaviors that promote the problem. While medications do not help with weight gain, they may be used to help with associated anxiety or depression.