Antipsychotic Medicines

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Antipsychotics are medicines that are mainly used to treat schizophrenia or mania caused by bipolar disorder. There are two main types of antipsychotics: atypical antipsychotics and older antipsychotics. Both types are thought to work as well as each other. Side-effects are common with antipsychotics. You will need regular tests to monitor for side-effects while you take these medicines.

Antipsychotics are a group of medicines that are mainly used to treat mental health illnesses such as schizophrenia, or mania (where you feel high or elated) caused by bipolar disorder. They can also be used to treat severe depression and severe anxiety. Antipsychotics are sometimes also called major tranquillisers.

There are two main types of antipsychotics:

Antipsychotics are available as tablets, capsules, liquids and depot injections (long-acting). They come in various different brand names.

Older antipsychotics have been used since the 1950s and are still prescribed today. Newer antipsychotics were developed in the 1970s onwards. It was originally thought that these medicines would have fewer side-effects than the older type of antipsychotics. However, we now know that they can also cause quite a few side-effects.

Antipsychotics are thought to work by altering the effect of certain chemicals in the brain, called dopamine, serotonin, noradrenaline and acetylcholine. These chemicals have the effect of changing your behaviour, mood and emotions. Dopamine is the main chemical that these medicines have an effect on.

By altering the effects of these chemicals in the brain they can suppress or prevent you from experiencing:

  • Hallucinations (such as hearing voices).
  • Delusions (having ideas not based on reality).
  • Thought disorder.
  • Extreme mood swings that are associated with bipolar disorder.

As discussed above, antipsychotics are usually prescribed to help ease the symptoms of schizophrenia, mania (caused by bipolar disorder), severe depression or severe anxiety. Normally they are started by a specialist in psychiatry, or your GP will ask a specialist for advice on when to start them.

Also, for many years antipsychotics were used to calm elderly people who had dementia. However, this use is no longer recommended. This is because these medicines are thought to increase the risk of stroke and early death - by a small amount. Risperidone is the only antipsychotic recommended for use in these people. Even then, it should only be used for short period of time (less than six weeks) and for severe symptoms.

The choice of antipsychotic prescribed depends upon what is being treated, how severe your symptoms are and if you have any other health problems. There are a number of differences between the various antipsychotic medicines. For example, some are more sedating than others. Therefore, one may be better for one individual than for another. A specialist in psychiatry usually advises on which to use in each case. It is difficult to tell which antipsychotic will work well for you. If one does not work so well, a different one is often tried and may work well. Your doctor will advise.

It is thought that the older and newer types of antipsychotics work as well as each other. The exception to this is clozapine - it is the only antipsychotic that is thought to work better than the others. Unfortunately, clozapine has a number of possible serious side-effects, especially on your blood cells. This means that people who take clozapine have to have regular blood tests.

In some cases, an injection of a long-acting antipsychotic medicine (depot injection) is used once symptoms have eased. The medicine from a depot injection is slowly released into the body and is given every 2-4 weeks. This aims to prevent relapses (recurrences of symptoms). The main advantage of depot injections is that you do not have to remember to take tablets every day.

It is thought that for every 10 people who take these medicines, 8 will experience an improvement in their symptoms. Unfortunately, antipsychotics do not always make the symptoms go away completely, or for ever. A lot people need to take them in the long term even if they feel well. This is in order to stop their symptoms from coming back. Even if you take these medicines on a long-term basis and they are helping, sometimes your symptoms can come back.

Symptoms may take 2-4 weeks to ease after starting medication and it can take several weeks for full improvement. The dose of the medicine is usually built up gradually to help to prevent side-effects (including weight gain).

This depends on various things. Some people may only need to take them for a few weeks but others may need to take them long-term (for example, for schizophrenia). Even when symptoms ease, antipsychotic medication is normally continued long-term if you have schizophrenia. This aims to prevent relapses, or to limit the number and severity of relapses. However, if you only have one episode of symptoms of schizophrenia that clears completely with treatment, one option is to try coming off medication after 1-2 years. Your doctor will advise.

If you want to stop taking an antipsychotic you should always talk to your doctor first. This is in order to help you decide if stopping is the best thing for you and how you should stop taking your medicine. These medicines are usually stopped slowly over a number of weeks. If you stop taking an antipsychotic medicine suddenly, you may become unwell quite quickly. Your doctor will usually advise you to reduce the dose slowly to see what effect the lower dose has on your symptoms.

Side-effects can sometimes be troublesome. There is often a trade-off between easing symptoms and having to put up with some side-effects from treatment. The different antipsychotic medicines can have different types of side-effects. Also, sometimes one medicine causes side-effects in some people and not in others. Therefore, it is not unusual to try two or more different medicines before one is found that is best suited to an individual.

The following are the main side-effects that sometimes occur. However, you should read the information leaflet that comes in each medicine packet for a full list of possible side-effects.

Common side-effects include:

  • Dry mouth, blurred vision, flushing and constipation. These may ease off when you become used to the medicine.
  • Drowsiness (sedation), which is also common but may be an indication that the dose is too high. A reduced dose may be an option.
  • Weight gain which some people develop. Weight gain may increase the risk of developing diabetes and heart problems in the longer term. This appears to be a particular problem with the atypical antipsychotics - notably, clozapine and olanzapine.
  • Movement disorders which develop in some cases. These include:
    • Parkinsonism - this can cause symptoms similar to those that occur in people with Parkinson's disease - for example, tremor and muscle stiffness.
    • Akathisia - this is like a restlessness of the legs.
    • Dystonia - this means abnormal movements of the face and body.
    • Tardive dyskinesia (TD) - this is a movement disorder that can occur if you take antipsychotics for several years. It causes rhythmical, involuntary movements. These are usually lip-smacking and tongue-rotating movements, although it can affect the arms and legs too. About 1 in 5 people treated with typical antipsychotics eventually develop TD.

Atypical antipsychotic medicines are thought to be less likely to cause movement disorder side-effects than typical antipsychotic medicines. This reduced incidence of movement disorder is the main reason why an atypical antipsychotic is often used first-line. Atypicals do, however, have their own risks - in particular, the risk of weight gain. If movement disorder side-effects occur then other medicines may be used to try to counteract them.

Your doctor will want to monitor you regularly for side-effects if you take an antipsychotic. The tests needed and how often you will need to have them depend on which antipsychotic you are taking.

In general, your doctor will take a sample of blood for certain tests before you start treatment. The tests look at:

  • How many blood cells you have.
  • How well your kidneys and liver are working.
  • How much lipid (fat) is in your blood.
  • Whether you have diabetes.

These tests may be repeated in the first three or four months of treatment. After this they are normally done every year. However, your doctor may advise you to have these tests more often.

Your weight and blood pressure are usually measured before you start treatment and every few weeks after this for the first few months. After this they are normally measured every year.

The blood level of prolactin (a hormone) may also be measured before starting treatment and six months later. Usually it is then measured every year after this. The prolactin level is measured because sometimes antipsychotics can make you produce too much of this hormone. If you make too much prolactin it can lead to your breasts growing bigger and breast milk being produced.

Note: people taking clozapine need weekly blood tests for the first six months and two-weekly blood tests after that. This is because it can have a serious effect on how many blood cells you make.

Antipsychotics are usually not prescribed for people who are in a coma (comatose), have depression of their central nervous system, or who have a tumour on the adrenal gland (phaeochromocytoma).

No - they are only available from your pharmacist, with a doctor's prescription.

If you think you have had a side-effect to one of your medicines, you can report this on the Yellow Card Scheme. You can do this online at the following web address:

The Yellow Card Scheme is used to make pharmacists, doctors and nurses aware of any new side-effects that your medicines or any other healthcare products may have caused. If you wish to report a side-effect, you will need to provide basic information about:

  • The side-effect.
  • The name of the medicine which you think caused it.
  • The person who had the side-effect.
  • Your contact details as the reporter of the side-effect.

It is helpful if you have your medication and/or the leaflet that came with it with you while you fill out the report.

Further help & information

Original Author:
Jenny Whitehall
Current Version:
Peer Reviewer:
Dr Laurence Knott
Document ID:
13868 (v3)
Last Checked:
Next Review:
The Information Standard - certified member
Now read about Psychosis - Diagnosis and Management

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