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), family therapy, and self-help measures.
What is anorexia nervosa?
Anorexia nervosa (just called anorexia from now on) is an eating disorder. It is ten times as common in females as in males. It most often starts during teenage years. About 9 in 1,000 women develop features of anorexia at some point in their lives.
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 'water' tablets (diuretics).
If you are a teenager, and still growing, you may not lose weight, but you may not be gaining it as you should. The result will be the same, ie you are under the normal weight for your age and height.
People with anorexia typically weigh 15% or more below the expected weight for their age, sex and height. Your 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. If you are under 18 years of age, normal weight is assessed by using special age-related BMI charts.
With anorexia, you feel very in control of your body weight 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.
An unrealistic image of own 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.
Studies show that if you are anorexic, what you see when you look at yourself in the mirror is different to what other people see. If you were asked to draw, or match a computer image of what you think you look like, you may think you are bigger than you really are.
It is common for people with anorexia to:
- Vomit secretly after eating.
- Try hard to hide their thinness - for example, by wearing baggy clothes, or putting heavy objects in their pockets when being weighed.
- 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.
Physical symptoms caused by low body weight or poor diet
These are many, but can include:
- Dizziness or fainting
- Feeling cold a lot of the time
- Irregular sleeping patterns
- Poor concentration
- Others detailed in the "health risks" section below
What are the health risks with anorexia nervosa?
Health risks are caused by under-eating (starvation) and by the methods used to get rid of eaten food - being sick (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 unable to have a baby (infertile).
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 muscle spasms (tetany). Anorexia can also cause low sugar levels.
'Thinning' of the bones (osteoporosis)
Osteoporosis 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 tummy (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.
If you have anorexia, your body's defence system does not work as well, and you are more likely to develop infections.
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. Traumatic events such as sexual abuse may make anorexia more likely, as do some dieting experiences.
- There may be some genetic factor. Some studies of families with identical twins show that if one twin has anorexia then the other has a 1 in 2 chance of getting it. However, not all studies have had the same finding, so it is not known how much genetic factors are involved.
- Brain changes have been found in people with anorexia. It is not known if these are the result of starvation, or if they are involved in the cause.
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, low potassium levels, kidney or liver problems or a low glucose level. An ECG heart 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, dieticians and other professionals. Usually this will involve outpatient appointments. Occasionally if you have very severe anorexia or medical complications, you may be admitted to a specialised eating disorder unit, or a medical ward in hospital. Medication is not usually necessary in treating anorexia.
The sorts of treatments that may be offered include the following:
Help with eating
It is best to have regular meals. 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
Examples of talking treatments used are cognitive behavioural therapy (CBT), cognitive analytic therapy (CAT), interpersonal psychotherapy (IPT) and focal psychodynamic therapy. Families are involved in therapy as much as possible, especially for young people with anorexia. Talking treatments help to look at the reasons why you may have developed anorexia. They 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.
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 (diuretics). Taking hormones may be recommended (for example, the oral contraceptive pill) to increase your body's oestrogen levels. Other tablets may be recommended to help strengthen your bones.
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 self-help techniques involve guidance from one of the therapists in the eating disorders specialist team.
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. About half of all people with anorexia (5 in 10) get completely better. About 3 in 10 improve so the anorexia has less impact on their life, and 2 in 10 continue to live with an eating disorder.
Unfortunately, some people with anorexia die from causes related to anorexia. It is thought around 3 in every 100 people with anorexia die from it. Causes of death include infections, lack of fluid in the body (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 (January 2004)
- Eating disorders; NICE CKS, October 2014 (UK access only)
- 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.
- Rikani AA, Choudhry Z, Choudhry AM, et al; A critique of the literature on etiology of eating disorders. Ann Neurosci. 2013 Oct;20(4):157-61. doi: 10.5214/ans.0972.7531.200409.
- Eating disorder information; Academy for Eating Disorders
- Body Mass Index (BMI) charts for girls and boys age 2-18; Royal College of Paediatrics and Child Health and Dept of Health.
- Hay PJ, Sachdev P; Brain dysfunction in anorexia nervosa: cause or consequence of under-nutrition? Curr Opin Psychiatry. 2011 May;24(3):251-6.
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 Mary Harding
Dr John Cox