This information is for people who have anorexia. It tells you about antipsychotic drugs, a treatment that's sometimes used for anorexia. It is based on the best and most up-to-date research.
Do they work?
We don't know. There hasn't been any good research on antipsychotic drugs as a treatment for people with anorexia. But we do know that they cause side effects, including heart problems. These can be very dangerous for people with anorexia.
What are they?
Antipsychotic drugs are usually used to treat mental health problems such as schizophrenia. People with schizophrenia have periods of time when they are out of contact with reality. They may hear things, often voices, that aren't really there, and they may have strange beliefs and feel very tense and jumpy. Doctors call this kind of illness psychosis. Medicines used to treat it help people feel much calmer.
Having anorexia is not the same as having psychosis. It's a very different kind of illness.
When these drugs have been used to treat anorexia, it's because they can have a calming effect. They are also used because one of their side effects is that people taking them tend to put on weight. And sometimes these drugs are given to people with anorexia who also have other serious mental health problems. 
Common antipsychotic drugs (with their brand names) include:
There are also newer antipsychotic drugs, called atypical antipsychotics. They may have fewer side effects than the older kind:
To find out more about how anorexia is treated, see What you can expect from the NHS.
How can they help?
There hasn't been much research looking at whether antipsychotic drugs can help people with anorexia feel less anxious about eating or putting on weight. A few studies hint that newer antipsychotics, such as olanzapine, might help.   
But most of the studies are small or not very good-quality.
How do they work?
Antipsychotic drugs reduce the effects of a chemical in your brain called dopamine. Dopamine affects your thoughts and your emotions, and it helps control how your muscles move. Researchers don't really know why changing the level of dopamine might help ease feelings of fear, worry, and agitation.  
Can they be harmful?
We don't know exactly what side effects you might get if you take an antipsychotic drug for anorexia. But studies of people taking this drug for other mental health problems show some serious side effects. They include: 
A dry mouth
Skin that is sensitive to the sun
A twitching head and twitching neck and face muscles. The newer antipsychotic drugs, such as olanzapine, are less likely to cause this side effect
Problems with the electrical signals that help control your heart rate.