What is it?
Anorexia nervosa is an eating disorder characterized by an obsessive relationship with weight and eating. Even though sufferers have often starved themselves to the point of severe underweight, they tend to see themselves as fat. They often weigh themselves regularly, exercise a lot, and eat only very small amounts of a very restricted selection of foods. People with anorexia can be very defensive about their behavior, and not acknowledge that they have a problem.
Anorexia affects about 0.9-4.3% of women and 0.2-0.3% of men in Western countries during their lifetime. It is particularly common in people such as dancers and models, who are under a heavy pressure to maintain a low weight. It commonly begins during puberty. About 1 in 20 people with anorexia die because of it over the course of a ten-year period.
What causes it?
While the exact cause of anorexia hasn’t been identified, it is associated with many factors.
Twin studies have found that there is as high a heredity rate as 28-58%. This probably has something to do with things like the function of reward and motivation mechanisms, and personality traits. Having a gastrointestinal disease such as celiac disease has been associated with a higher prevalence of anorexia. This might be the case because people living with such diseases have already developed a habit of avoiding certain foods, and it’s easier to “slip” into an eating disorder.
There is an abundance of hypotheses attempting to explain from a more abstract perspective why some people get anorexia. According to one, for example, during puberty girls might feel that they are not in control of the changes in their lives and bodies, and become addicted to the rush of power they get when they manage to control their bodies.
What happens during it?
Our brain remodels itself all the time based on our experiences. If we get satisfaction of something like, say, completing a math assignment successfully, that network in our brain gets a little bit stronger and we are likely to do math assignments a little bit more eagerly next time. This is basically the same mechanism that is thought to lead to anorexia. The typical patient is someone who has been on the higher side of the weight scale (though not necessarily overweight), and decided to loose a bit of weight. When they succeed in this, they are both proud of themselves and probably also get compliments from their friends and family. This process boosts the positive feelings they have associated with limiting their eating and doing more exercise. The patients also start to associate negative feelings with food. A similar process probably happens here as described before. It’s essential to learning that the brain learns to fear certain things, and this can happen when we consciously avoid something – it’s a useful survival strategy when it comes to poisonous snakes, but not as useful when we put something as essential as food in the same category as poisonous snakes. If we always punish ourselves when we eat “too much” and start to hate food, we will develop circuits that are fooled by our behavior to believe that food is something scary and dangerous. If this pattern continues for a while, the patient’s behavior has caused such big changes to some of the brain’s anxiety and reward mechanisms, that escaping their impacts is very hard and time-consuming.
How can it be treated?
The treatment of anorexia has three main focuses. The person should be restored to a healthy weight, the psychological disorders related to the disease should be treated, and the behaviors and thoughts that originally lead to the disease should be eliminated.
Encouraging and helping the patient to eat varied, energy-dense food is probably the most important thing to do. Many kinds of therapies, either involving only the patient or both the patient and their family, have been proven to be useful. Sometimes the patient is in such a bad shape that hospitalization may be necessary to keep them alive.
About half of anorexia patients achieve full recovery. It is often said, however, that while recovery is very much possible and definitely encouraged, there is no going back to how things used to be once someone has been through anorexia.
Sources: https://en.wikipedia.org/wiki/Anorexia_nervosa, http://emedicine.medscape.com/article/912187-overview?pa=lvQoDibjmZvKxDhCmrA7LSIhmJfYzwJIWajbQrMZiKwyePggNS2A25c8L3rOw3JAVrJxKJt4DRD8mxYr6kYfOw%3D%3D#a3, http://bestpractice.bmj.com/best-practice/monograph/440/basics/pathophysiology.html,