Anorexia nervosa is an eating disorder. A person with anorexia nervosa deliberately loses weight and often finds that food dominates their life. The weight loss may become severe and life-threatening. Treatment includes talking treatments such as cognitive behavioural therapy (CBT), sometimes medication, and self-help measures.
What is anorexia nervosa?
Anorexia nervosa (just called anorexia from now on) is an eating disorder. Anorexia is a serious condition which affects all sorts of people. Anorexia is very common - about 1 in 20 teenagers has it. However, it affects people of all ages and has become more common in boys and men in recent years.
People with anorexia often find that they do not allow themselves to feel full after eating. This means that they restrict the amount they eat and drink. People with anorexia are underweight. Sometimes, the weight becomes so low that it is dangerous to health.
How do I know if I have an eating disorder?
If you answer yes to two or more of these questions then you may have an eating disorder and you should see your doctor:
- Do you make yourself sick because you are uncomfortably full?
- Do you worry that you've lost control over how much you eat?
- Have you recently lost more than 6 kg (about one stone) in the past three months?
- Do you believe you're fat when others think you are thin?
- Would you say that food dominates your life?
What are the symptoms of anorexia nervosa?
Deliberate weight loss
This is the main symptom. You lose weight by avoiding fattening foods or even any foods. People with anorexia limit the amount they eat and drink, in order to control how their body looks. You may often pretend to other people that you are eating far more than you actually are. You may be using other ways of staying thin such as exercising too much. You may also have made yourself vomit, take laxatives, or even take appetite suppressant medicines or diuretics (water tablets).
People with anorexia typically weigh 15% or more below the expected weight for their age, sex and height. The body mass index (BMI) is calculated by your weight (in kilograms) divided by the square of your height (in metres). For example, if you weigh 66 kg and are 1.7 m tall then your BMI would be 66/(1.7 x 1.7) = 22.8. A normal BMI for an adult is 20-25. Above that you are overweight, and below that you are underweight. Adults with anorexia have a BMI below 17.5.
With anorexia, you feel very in control of your bodyweight and shape. However, with time, anorexia can take control of you. After some time it can become very difficult to make healthy, normal choices about the amount and types of food you eat.
A wrong idea of body size
People with anorexia think that they are fat when they are actually very thin. Although other people see you as thin or underweight, it is very difficult for you to see this. You are likely to have a severe dread (like a phobia) of gaining weight. People with anorexia will do their utmost to avoid putting on weight.
It is common for people with anorexia to:
- Vomit secretly after eating.
- Try hard to hide their thinness - for example, by wearing baggy clothes.
- Tend not to be truthful about how much they eat and everything to do with food.
- Like food and feel hungry. However, it is the consequences of eating that frighten them.
People with anorexia may also become obsessed with what other people are eating.
People with anorexia often restrict themselves to certain types of food. Eating food may even become like a ritual. For example, each time you eat, you have to cut your food into very small pieces. You may think frequently about your weight and even weigh yourself most days or even several times a day. It is also common to feel cold most of the time and to have irregular sleeping patterns. You might also find yourself having poor concentration.
What are the health risks with anorexia nervosa?
Health risks are caused by undereating (starvation) and by the methods used to get rid of eaten food (vomiting, excess laxatives, etc). Problems that may occur include the following:
Many women with anorexia have irregular periods, as hormone levels can be affected by poor diet. Their periods may even stop altogether or they may find that their periods have never started, especially if they started having eating problems when they were younger. Some women with anorexia may be infertile (unable to have a baby).
Chemical imbalances in the body
These are caused either by repeated vomiting or by excess use of laxatives - for example, a low potassium level which may cause tiredness, weakness, abnormal heart rhythms, kidney damage and convulsions. Low calcium levels can lead to tetany (muscle spasms).
Thinning of the bones (osteoporosis)
This is caused by a lack of calcium and vitamin D and can lead to easily fractured bones. In addition, the risk of getting osteoporosis increases if you are a woman and your periods have stopped. This is because oestrogen in your body protects your bones from osteoporosis and the levels of oestrogen in your body reduce when your periods stop.
These may occur if you take a lot of laxatives. Laxatives can damage the bowel muscle and nerve endings. This may eventually result in permanent constipation and also sometimes abdominal pains.
Swelling of hands, feet and face
This is usually due to fluid disturbances in the body.
These can be caused by the acid from the stomach rotting away the enamel with repeated vomiting.
Having a diet low in iron can lead to anaemia. This can make you feel weaker and more tired than normal. Dizzy spells and feeling faint can also occur.
It is common to feel low when you have anorexia. Some people develop clinical depression, which can respond well to treatment. It is important to talk to your doctor about any symptoms of depression you may have. Many people find they become more moody or irritable.
Hair and skin problems
You may find you have downy hair on your body and also the hair on your head becomes thinner. Many people with anorexia also have dry, rough skin.
What is the cause of anorexia nervosa?
The exact cause is not fully understood. Part of the cause is a fear of getting fat but it is not just as simple as that. Different causes possibly work together to bring on the condition. These may include the following:
- The pressure from society and the media to be thin is thought to play a part. This is probably why anorexia is much more common in westernised countries.
- Personality and family environment probably play a role too. People with anorexia often have poor self-esteem (not much self-confidence) and commonly feel that they have to be perfectionists. Often there are disturbed family relationships. All sorts of emotions, feelings and attitudes may contribute to causing anorexia.
- There may be some genetic factor. We know this from studies of families with identical twins. If one twin has anorexia then the other has a 1 in 2 chance of getting it. This tells us that the condition may have a genetic part. However, because not every twin gets it, there are other factors too.
Are any tests needed?
Although there is no test to diagnose anorexia, your doctor may wish to do some tests. These may include blood tests to check for complications of anorexia - for example, anaemia, potassium levels, kidney or liver problems or a low glucose level. An ECG hear tracing (electrocardiography) may be advised to check for an irregular heart rhythm.
What is the treatment for anorexia nervosa?
The aim of treatment is to:
- Reduce risk of harm (and death) which can be caused by anorexia.
- Encourage weight gain and healthy eating.
- Reduce other related symptoms and problems.
- Help people become both physically and mentally stronger.
You are likely to be referred to a specialist mental health team which includes psychiatrists, psychologists, nurses, dietitians and other professionals. If you have more severe anorexia, you may be referred to a specialist eating disorder unit.
The sort of treatments that may be offered include the following:
Help with eating
Having regular meals is better. Even if you only eat small meals it is beneficial to the body to eat at least three times a day. You should try to be honest (with yourself and other people) about the amount of food you are actually eating. You should reduce the number of times you weigh yourself; try to weigh yourself only once a week. It may be useful to keep an eating diary to write down all the food that you eat.
Psychological (talking) treatments
For example, cognitive behavioural therapy (CBT), cognitive analytic therapy (CAT), interpersonal psychotherapy (IPT) and focal psychodynamic therapy. Talking treatments help to look at the reasons why you may have developed anorexia, and aim to change any false beliefs that you may have about your weight and body, and to help show you how to identify and deal with emotional issues. Talking treatments take time and usually require regular sessions over several months. Treatment may also involve other members of your family going to meetings to discuss any family issues.
This may be advised in addition to talking treatments if you also develop depression. These are not always recommended if you are younger than 18 years old.
Treatment of any physical or teeth problems that may occur
This may include taking potassium supplements, having dental care and trying not to use laxatives or water tablets. You may be recommend to take hormones (for example, the oral contraceptive pill) to increase levels of oestrogen in your body to help strengthen your bones.
Self-help measures may be of benefit
There are a number of self-help books and guides available. These provide methods on how to cope with and overcome anorexia. (Beat - the Eating Disorders Association listed at the end - may be able to suggest current titles.) They are not suitable for everyone, particularly if your anorexia is severe.
Some people with more severe anorexia may need to have a short stay in hospital.
What is the outlook (prognosis)?
With treatment, anorexia can take weeks or even many months to improve. It can take several years for people with anorexia to become completely better. Many people find they still have issues with food, even after treatment, but they are more in control and can lead happier, more fulfilled lives.
Unfortunately, some people with anorexia die from causes related to anorexia. Causes of death include infections, dehydration, blood chemical imbalances (such as low potassium levels) and even suicide.
Further help & information
Further reading & references
- Eating disorders - core interventions in the treatment and management of anorexia nervosa, bulimia nervosa and related eating disorders; NICE (2004)
- Eating disorders; NICE CKS, October 2009
- Hay PJ, Sachdev P; Brain dysfunction in anorexia nervosa: cause or consequence of under-nutrition? Curr Opin Psychiatry. 2011 May;24(3):251-6.
- Treasure J, Claudino AM, Zucker N; Eating disorders. Lancet. 2010 Feb 13;375(9714):583-93.
- Morris J, Twaddle S; Anorexia nervosa. BMJ. 2007 Apr 28;334(7599):894-8.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Tim Kenny
Dr Louise Newson
Dr John Cox