The impulse to eat is one of the basic survival instincts of all animal life on Earth. Most of us eat not only because we need to, but because we enjoy it.

That's why anorexia¹ nervosa can be so difficult to understand. A psychiatric disorder in which people stop eating the food they need to survive, accompanied by a dangerous distortion in the way they view their bodies, seems counter to everything that has helped humans survive thus far. Nonetheless it is a well-known problem throughout the world.

Signs of the Disorder

When suffering from anorexia people lose weight excessively, to the point where they have a weight far below that which is healthy. This can be due to the individual seriously reducing their food intake (sometimes stopping their eating entirely), although there is a subtype of anorexia in which people have eating binges, followed by eliminating the energy they've just eaten (either by rigorous exercise programmes, by vomiting or by using laxatives). Most people associate binge-eating with the related disorder of bulimia nervosa, but it can occur in anorexic individuals too².

This abnormal eating behaviour is coupled with an intense fear of gaining weight. Anorexic individuals almost invariably have an abnormal sense of their own body image, and often continue to see themselves as fat even when they are starving and skeletal. An anorexic individual's body shape usually has a much larger part in determining their self-esteem than their other, non-physical qualities.

In anorexia, monthly periods stop; physical growth and sexual development may also be slowed or halted if the anorexia starts when the physical changes of puberty are still going on (these changes continue for most of the teenage years). As people get thinner and their nutrition remains poor, other problems begin to take shape:

• Muscles wasting away.

• Brittle bones.

• Scaly skin.

• Loss of hair on the scalp, but a soft, white down-like hair may develop on the face and forearms.

• Dropping body temperature (due to the loss of the normal fat that usually acts as an insulator).

• Vitamin and mineral deficiency, with all the associated complications.

• Imbalances in the body's chemical makeup (including abnormal levels of important chemicals like sodium, potassium and calcium) which can lead to heart arrhythmias and sometimes subsequent heart failure (which is the most serious, and sometimes fatal, complication).

Demographics

Anorexia can affect anyone. Historically, it was seen almost entirely in adolescent and young adult women living in Western cultures - however, with the spread of Western movies and images, other parts of the world are beginning to notice more people with the disorder. Females with anorexia outnumber males by nine to one, but reports of men who display anorexic symptoms are becoming more common.

Causes

Like most psychiatric disorders, the problem is probably a combination of all sorts of different factors. There is a genetic component, shown in twin studies where an identical twin of an anorexic individual (who had shared the same environment growing up) was much more likely to get the disorder than a non-identical twin in the same situation. People who have had, or have family histories of, eating disorders, depression, anxiety and particularly obsessive-compulsive disorders (with their associated personality traits, like perfectionism and the need for control) are more prone to developing anorexia as well, suggesting that the disorders are linked in some way.

Because the syndrome is so closely bound to Western countries, with its prominent dieting culture and worship of the 'ideal' (read: often unrealistically thin) body, many people have laid the blame squarely at the feet of society. It's definitely true that anorexia most commonly starts with the individual's decision to go on a diet because of pressure from friends, family or the media. Athletes such as gymnasts and jockeys, who participate in sports which often have harsh weight requirements, are more prone to the disorder as well. However, why some people get the disorder and others don't is still unknown.

Treatment

As is usual in medicine, prevention is far better than cure. In the early stages of the disorder, kind and supportive words and honest discussions around body image can often be quite helpful - the loss of perspective and fixation on the 'ideal' body size and shape can hopefully be prevented.

There are many different kinds of psychotherapy used for anorexia once it is established – cognitive behavioural therapy (a type of psychotherapy that focuses on giving patients strategies to prevent and deal with negative thoughts) is a common one. Not every treatment works for every person, though, so sometimes several different methods (or therapists) need to be tried.

Another example of a technique that is sometimes used is 'externalising' the anorexia, making it something outside of the individual. The therapist will encourage their patient to think of her symptoms as a separate personality from herself; one that can be fought against and controlled.

Psychotherapy can be astonishingly successful. Unfortunately, sometimes the anorexic individual's condition worsens despite therapy. Some only present themselves to medical services when they are emaciated and starving. These people can become life-threateningly ill due to starvation. In this state the mind doesn't work properly due to very low bodyweight and associated chemical imbalances, and these individuals mostly need treatment in hospital with feeding (either orally, or through a tube if the patient doesn't take food orally). Staff at the hospital will prevent patients in this situation from doing any exercise unless they eat, in order to make sure more energy is going in than is going out. It's also worth noting that sometimes competitions around weight can arise between anorexic individuals who are hospitalised at the same time. Above a certain watershed weight, some of the chemical imbalance in the brain resolves, the individual becomes a better candidate for psychotherapy, and a more co-operative approach can be used.

There is some early evidence for the use of pro-kinetic agents that make the bowel move faster (such as cisapride), low-dose antipsychotics and antidepressants to help with weight gain in anorexia. Many trials are going on to assess the effectiveness of these and other medications, but their detailed use is beyond the scope of this Entry.

Pro-anorexic Culture

On the opposite end of the scale to treatment options there are groups who don't consider anorexia a destructive illness. Instead, they see the disorder as either a religion, a variation on 'normal' dieting regimes, an active socially conscious lifestyle choice or an intrinsic part of popular culture (or, more commonly, a combination of all of these) - despite the significant health risks outlined above. There are hundreds of pro-anorexic websites on the internet, but most are blocked by the major search engines. They contain many references to celebrities that are presumed to have eating disorders, anorexic pornography, and pages detailing the 'Ana Creed' and the 'Ana Prayer'.

Remember...

Unfortunately, despite the best efforts of families and medical services, some patients don't make it through their illness. Anorexia can be fatal, and if you or someone you know is displaying the signs mentioned above, make sure the affected person seeks medical attention urgently.