Neuromodulation in Anorexia Nervosa

Introduction

Anorexia nervosa (AN) is a chronic and debilitating illness with a prevalence of 0.3%–0.9% in the general population ( ). The disorder is 10 times more common in women, being typically diagnosed in adolescents ( ) between the ages of 15 and 21. Patients identified during adulthood are usually those who have suffered from the disease for many years prior to diagnosis ( ).

Clinical Aspects

AN comprises a multitude of clinical, psychiatric, and psychological symptoms that are not only primary to the disorder but may also be a consequence of weight loss and starvation ( ).

Usual symptoms are weight loss or failure to gain weight, excessive worry about weight and body image, checking behaviors, and the misperception of being fat. To lose weight or maintain a low weight gain, patients often exercise in excess, diet, and develop rules and strategies to control food intake.

Perceptual disturbances specifically involving weight and shape are common in AN. Patients perceive their own body as being fat, despite clear evidence to the contrary ( ). Behaviors such as body checking, frequent weighing, meticulous recording of weight changes, and keeping track of body shape by measuring changes with time all serve to reinforce pathological thinking ( ). Psychiatric symptoms commonly observed in AN are depressed mood, anxiety, obsessions, compulsions, and affective dysregulation ( ). These are often related to comorbid psychiatric disorders, mainly depression, anxiety, and obsessive–compulsive disorder (OCD) ( ).

Perhaps as important as the core symptoms of the disease are the health consequences of starvation and malnourishment ( ). Patients often present muscle atrophy, weakness, fatigue, lethargy, osteopenia, and osteoporosis, which may result in pathological fractures. They may also develop anemia, arrhythmias, heart problems, low blood pressure, dehydration, and metabolic problems, including dangerously altered levels of potassium and sodium. Their skin and nails may become dry and brittle. Hair loss may occur. In patients who vomit and purge, cavities, esophageal tears, and reflux are not unusual. Endocrinological problems and changes in the hypothalamic–pituitary–adrenal axis are particularly common. Prepubertal patients may have a delayed sexual maturity and growth failure. After puberty patients may develop amenorrhea (previously considered as a diagnostic criterion) ( ).