Antipsychotic medicines

Key points about antipsychotic medicines

  • Antipsychotic medicines are used to treat some types of mental distress or conditions.
  • They can also be used to help anxiety or depression where it is severe or difficult to treat. 
  • Find out how to take them safely and possible side effects.
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Antipsychotic medicines are used to treat some types of mental illnesses such as schizophrenia and bipolar disorder. They can also be used to help anxiety or depression where it is severe or difficult to treat. 

Antipsychotic medicines don't cure these conditions. They are used to help ease the symptoms and help you on your recovery path. They can help with symptoms such as extreme mood swings of bipolar disorder, the experience of hearing voices (hallucinations), ideas that distress you and don't seem to be based in reality (delusions) and difficulty in thinking clearly (thought disorder). When taken over a longer term, antipsychotic medicines can help to prevent further episodes of psychosis.

  • Most antipsychotic medicines are tablets, capsules or liquid taken every day. 
  • Some antipsychotic medicines (eg, olanzapine and risperidone) are available as an injection. 
  • The long-acting or depot injection is an option when your symptoms have settled after taking tablets, capsules or a liquid. Read more about depot antipsychotics.

For more information about psychosis, antipsychotic medicines and the common concerns about them, see Talking Minds, NZ(external link).

The following video gives more information about psychosis and antipsychotic medicines.

(external link)

(Werry Workforce, 2018)

Antipsychotic medicines are divided into 2 main groups – typical antipsychotics and atypical antipsychotics. They are slightly different and also have different side effects.

Typical antipsychotics
Examples of typical antipsychotics are zuclopenthixol, haloperidol and chlorpromazine.
  • These are known as first-generation antipsychotics and are the older type antipsychotics.
  • They're not all the same, for example, some may cause more severe side effects such as movement disorders, others may be more likely to make you drowsy.
 Atypical antipsychotics
Examples of atypical antipsychotics amisulpride, aripiprazole, clozapine, olanzapine, quetiapine, risperidone and ziprasidone
  • These are known as second-generation antipsychotics and are the newer type of antipsychotics.
  • Generally they are less likely to cause side effects, including sexual side effects, than first generation antipsychotics.
  • However, second generation antipsychotics may be more likely to cause weight gain and changes to blood glucose levels.

Antipsychotic medicines affect the action of chemicals in the brain called neurotransmitters. These are chemicals your brain cells need to communicate with each other.

  • Dopamine is the main neurotransmitter affected by antipsychotic medicines. If parts of the dopamine system become overactive, it is thought that this may cause hallucinations, delusions and thought disorder. Dopamine is also involved in muscle movements. 
  • Most antipsychotic medicines also affect other neurotransmitters such as serotonin and noradrenaline, which are both thought to be involved in regulating mood.

Taking antipsychotic medicines won't change your personality and they're not addictive. When starting an antipsychotic medicine, give it time to start working properly.

The antipsychotic medicine you're prescribed will depend on:

  • the severity and nature of your illness
  • other medical conditions you may have
  • other medicines you are currently taking
  • your response to your medicine
  • past experiences of taking antipsychotic medicines (what has and hasn’t worked for you in the past)  
  • other considerations, eg, whether you need your medicine in a different form such as an injection instead of tablets, capsules or liquids.

Different people respond differently to antipsychotic medicines, so finding the best one for you may be a process of ‘trial and error’, where you have to try a few before you find the right one. It can take time to find the right type and dose to manage your symptoms.

As different antipsychotic medicines can have different side effects, it's important to talk to your doctor about the possible side effects and how they might affect your lifestyle. That will guide the decision about what's the best option for you. See Talking Minds, NZ(external link)  that enables you to explore and compare different medicines and their side effects so you and your healthcare team can decide which option is best for you. 

The following resource provides more information about things to think about when choosing an antipsychotic medicine. Be aware that websites from other countries may have information that differs from New Zealand recommendations and may mention different medicines.

If any of the following situations apply to you, discuss your options with your doctor before taking antipsychotic medicines as extra care may be needed.

  • Heart problems such as an irregular heartbeat or low blood pressure.
  • Parkinson’s Disease or epilepsy.
  • Depression.
  • Prostate problems.
  • Glaucoma.  
  • Diabetes or problems with high cholesterol.
  • You're pregnant or breastfeeding.
  • You're taking any other medicines, including medicines you can buy without a prescription, such as herbal and complementary medicines.
  • You smoke
  • You drink coffee regularly.

How long you'll need to take antipsychotic medicine depends on your symptoms. Some people need to keep taking it long-term. For example, for psychosis:

  • If you have only had one psychotic episode and you have recovered well, you would normally need to continue treatment for 1–2 years after recovery.
  • If you have another psychotic episode, you may need to take antipsychotic medicine for longer, up to 5 years. This is because the risk of symptoms recurring (relapse) is high for the first few years after a psychotic episode.
  • People who have had several psychotic episodes may need to keep taking antipsychotic medicine for most of their life. For other conditions, the length of time you need these medicines might be different.

If your symptoms are not improving, talk to your doctor about other options. There may be other medicines you can try, or other forms of medicine (such as a depot injection).

Most antipsychotic medicines seem to treat psychotic symptoms equally well. But, individuals react differently to them, particularly regarding their experience of side-effects. It is difficult to predict how well a particular person’s illness will respond to a particular antipsychotic medicine.

It's important to not stop taking your antipsychotic medicine suddenly as your symptoms may return if stopped too early; talk to your doctor or nurse before stopping. It is important to stay in contact with your doctor or mental health worker, even if you have been well for a few weeks or months without medication.

Some antipsychotic medicines can cause changes in your blood glucose level, your cholesterol level and in your heart function. To keep an eye out for these effects, your doctor will check your physical health.

  • You will have your weight measured regularly.
  • You may also need to have blood tests to check your kidneys, liver, cholesterol and glucose levels. If you're taking clozapine, you will need blood tests often.
  • You may also have your blood pressure measured, have an ECG test to check your heart rate and be given a laxative to manage constipation.
  • Women will need breast and bone density screening.

The following websites provide more information about antipsychotic medicines. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Antipsychotic medication(external link) The Royal Australian & New Zealand College of Psychiatrists
Antipsychotic Medicines(external link) Patient Info, UK
Antipsychotics(external link)


  1. Antipsychotic medication(external link) The Royal Australian & New Zealand College of Psychiatrists
  2. Antipsychotics(external link) Royal College of Psychiatrists, UK
  3. Antipsychotic drugs(external link) NZ Formulary

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