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Psychosis is a mental health problem that causes people to perceive or interpret things differently from those around them. This might involve hallucinations or delusions.

The two main symptoms of psychosis are:

  • hallucinations - where a person hears, sees and, in some cases, feels, smells or tastes things that aren't there; a common hallucination is hearing voices
  • delusions - where a person believes things that when examined rationally, are obviously untrue; such as believing that your next door neighbour is secretly planning to kill you

The combination of hallucinations and delusional thinking can cause an often severe disruption to perception, thinking, emotion and behaviour.

Experiencing symptoms of psychosis is often referred to as having a psychotic episode.

Read more about the symptoms of psychosis.


Psychosis is not a condition in itself - it is triggered by other conditions.

Sometimes it is possible to identify the cause of psychosis as specific a mental health condition, such as:

  • schizophrenia – a condition where people may have repeated episodes of psychosis
  • bipolar disorder –  a mental health condition that affects mood; a person with bipolar disorder can have episodes of depression (lows) and mania (highs)
  • severe depression – some people with depression also have symptoms of psychosis when they're very depressed

Psychosis can also be triggered by traumatic experiences, stress or physical conditions, such as Parkinson's disease, a brain tumour, or as a result of drug misuse or alcohol misuse.

How often a psychotic episode occurs and how long it lasts can depend on the underlying cause.

For example, schizophrenia can be long-term, but most people can make a good recovery, and about a quarter only have a single psychotic episode. Episodes related to bipolar disorder usually resolve, but may reoccur.

Diagnosing psychosis

You should see your GP immediately if you're experiencing psychotic episodes. It's important that psychosis is treated as soon as possible, because early treatment usually has better long-term outcomes.

Your GP will look at your symptoms and rule out short-term causes, such as drug misuse. They may ask you some questions to help determine what's causing your psychosis. For example, they may ask you:

  • whether you're taking any medication
  • whether you've been taking illegal substances
  • how your mood has been – for example, whether you've been depressed
  • how you've been functioning day-to-day – for example, whether you're still working
  • whether you have a family history of mental health conditions – such as schizophrenia
  • about your hallucinations – such as whether you've heard voices
  • about your delusions – such as whether you feel people are controlling you
  • whether you have any other symptoms

Your GP should refer you to a mental health specialist for further assessment and treatment.


Treatment for psychosis involves using a combination of:

  • antipsychotic medicines, which can help relieve symptoms of psychosis
  • psychological therapies, which can help address the underlying cause of the psychosis – for example the talking therapy cognitive behavioural therapy has proved successful in helping people with schizophrenia
  • social support – help to support the person with psychosis with social needs, such as education, employment or accommodation

Most people with psychosis who get better with medication need to continue taking it for at least a year. Some people need to take medication long term to prevent symptoms reoccurring.

If a person's psychotic episodes are severe, they may need to be admitted to a psychiatric hospital

Read more about the treatment of psychosis.

Getting help for others

People with psychosis often have what is known as a lack of insight, meaning they are unaware they are thinking and acting strangely.

Due to their lack of insight, it is often down to friends, relatives or carers of people affected by psychosis to seek help for them.

If you are concerned that someone you know may be affected by psychosis you could contact their social worker or community mental health nurse if they have previously been diagnosed with a mental health condition.

If you think the person’s symptoms are placing them at possible risk of harm then you can:

  • take the person to the nearest accident and emergency department, if they agree
  • call their GP or local out of hours GP
  • call NHS Direct Wales on 0845 4647
  • call 999 and ask for an ambulance

See diagnosing psychosis for more information on how get help for others.


People with a history of psychosis are much more likely to have drug and/or alcohol misuse problems. This may be because the use of these substances can provide short-term relief from symptoms (though they usually make symptoms worse in the long-term).

People with psychosis also have a higher than average risk of suicide. It's estimated that 1 in 5 people with psychosis will attempt to commit suicide at some point in their life, and 1 in 25 people with psychosis will kill themselves.

Side effects can also occur if taking antipsychotics on a long-term basis. Weight gain is a common side effect. In rare cases, a person with psychosis may also develop type 2 diabetes.

Who is affected?

Psychosis is more common than most people realise, with schizophrenia being the most commonly associated mental health condition. Research carried out in England in any given year, one new case of psychosis is diagnosed for every 2,000 people.

Another study estimated that around 3 in 100 people will have at least one episode of psychosis at some point during their life.

Psychosis can develop at any age, but is rare in children under 15.

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Someone who develops psychosis will have their own unique set of symptoms and experiences, according to their particular circumstances.

There are four main symptoms associated with a psychotic episode. These are:

  • hallucinations
  • delusions
  • confused and disturbed thoughts
  • a lack of insight and self-awareness

These are outlined in more detail below.


A hallucination is when you think you perceive something that does not exist in reality. Hallucinations can occur in all five of your senses:

  • Sight - someone with psychosis may see colours and shapes, or imaginary people, or animals.
  • Sounds - someone with psychosis may hear voices that are angry, unpleasant, or sarcastic
  • Touch - a common psychotic hallucination is that you are being touched when there is no-one there
  • Smell - usually a strange or unpleasant smell
  • Taste - some people with psychosis have complained of having a constant unpleasant taste in their mouth


A delusion is where you have an unshakable belief in something that is implausible, bizarre or obviously untrue. Two examples of psychotic delusion are:

  • paranoid delusion
  • delusions of grandeur

These are described below.

Paranoid delusion

A person with psychosis will often believe that an individual or organisation is making plans to hurt or kill them. This can lead to unusual behaviour. For example, a person with psychosis may refuse to be in the same room as a mobile phone because they believe they are actually mind-control devices.

Delusions of grandeur

A person with psychosis may have delusions of grandeur where they believes that they have some imaginary power or authority. For example, they may think they are president of a country, or have the power to bring people back from the dead.

Confusion of thought

People with psychosis often have disturbed, confused, and disrupted patterns of thought. Signs of this include that:

  • rapid and constant
  • random speech - for example, they may switch from one topic to another in mid-sentence
  • their train of thought may suddenly stop, resulting in an abrupt pause in conversation or activity

Lack of insight

People experiencing a psychotic episode are often totally unaware that their behaviour is in any way strange, or that the delusions or hallucinations could be imaginary.

They may be capable of recognising delusional or bizarre behaviour in others, but lack the self-awareness to recognise it themself. For example, a person with psychosis who is being treated in a psychiatric ward may complain that all of their fellow patients are mentally unwell while they are perfectly normal.

Postnatal psychosis

Postnatal psychosis, also called puerperal psychosis, is a severe form of postnatal depression (a type of depression some women experience after they have had a baby).

It is estimated that postnatal psychosis affects 1 in every 1,000 women who give birth, and most commonly occurs during the first few weeks after having a baby. Postnatal psychosis is more likely to occur in women who already have a mental health condition, such as bipolar disorder or schizophrenia.

As well as the other symptoms of psychosis (see above), symptoms of postnatal psychosis can include:

  • a high mood (mania)  for example, talking and thinking too much or too quickly
  • a low mood  for example, depression, lack of energy, loss of appetite and trouble sleeping

Postnatal psychosis is regarded as an emergency. If you are concerned someone you know may have developed postnatal psychosis contact your GP immediately. If this is not possible call NHS Direct Wales on 0845 46 47 or your local out-of-hours service.

If you think there is a danger of imminent harm you can call:

  • your local A&E services
  • NHS Direct Wales on 0845 46 47
  • 999 and ask for an ambulance
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The causes of psychosis have three main classifications:

  • psychosis caused by psychological (mental) conditions
  • psychosis caused by general medical conditions
  • psychosis caused by substances, such as alcohol or drugs

These three classifications are described in more detail below.

Psychological causes

The following conditions have been known to trigger psychotic episodes in some people:

  • schizophrenia, a chronic (long-term) mental health condition that causes hallucinations and delusions
  • bipolar disorder, previously called manic depression, bipolar disorder affects your moods, which can swing from one extreme to another
  • severe stress or anxiety
  • severe depression, feelings of extreme sadness that last for a long time(including postnatal depression, which some women experience after having a baby)
  • lack of sleep

The underlying psychological cause will often influence the type of psychotic episode experienced. For example, someone with bipolar disorder is more likely to have delusions of grandeur, whereas somebody with depression, or schizophrenia, is more likely to develop paranoid delusions (read more about the symptoms of psychosis.

General medical conditions

The following medical conditions have been known to trigger psychotic episodes in some people:

  • HIV/AIDS, a virus that attacks the body's immune system (the body’s natural defence against illness and infection)
  • malaria, a tropical disease that is spread by infected mosquitoes
  • syphilis, a bacterial infection that is usually passed on through sexual contact
  • Alzheimer's disease, the most common form of dementia that causes a decline of mental abilities, such as memory and reasoning
  • Parkinson's disease, a chronic condition that affects the way the brain co-ordinates body movements, including walking, talking and writing
  • hypoglycaemia an abnormally low level of sugar (glucose) in the blood
  • lupus a condition where your immune system attacks healthy tissue
  • lyme disease a bacterial infection that is spread to humans by infected ticks
  • multiple sclerosis a condition of the central nervous system (the brain and spinal cord), causing problems with muscle movement, balance and vision
  • brain tumour - a growth of cells in the brain that multiply in an abnormal and uncontrollable way


Alcohol and drug abuse can trigger a psychotic episode. A psychotic episode can also be triggered if you suddenly stop taking a drug or drinking alcohol after using it for a long time. This is known as withdrawal.

You can also experience psychosis after drinking large amounts of alcohol or if you are high on drugs.

Drugs known to trigger psychotic episodes include:

  • amphetamine (speed)
  • cocaine
  • methamphetamine (crystal meth)
  • mephedrone (MCAT or miaow)
  • MDMA (ecstasy)
  • cannabis
  • LSD (acid)
  • psilocybins (magic mushrooms)
  • ketamine

In rare situations, psychosis may also occur as a side-effect of some types of medication, or as a result of an overdose of that medication.

One example is levodopa, a medication used to treat Parkinson's disease, but any medicine that acts on the brain can cause psychosis with an overdose.

Never stop taking a prescribed medication unless advised to do so by your GP or another qualified healthcare professional who is responsible for your care. See your GP if you are experiencing psychotic side effects because of taking a medication.

The brain

There has been a great deal of research looking at how psychosis affects the brain and conversely how changes in the brain can trigger symptoms of psychosis.

Grey matter

Research has revealed that during a psychotic episode, several physical and biological changes occur in the brain.

The results of magnetic resonance imaging (MRI) scans carried out on people with a history of psychosis have shown that some people ,may have less grey matter than the average member of the general public. Grey matter is the part of the brain responsible for processing thoughts than most other people. However, it’s not yet fully understood why this is.


Researchers also believe that dopamine plays an important role in psychosis.

Dopamine is a neurotransmitter, one of many chemicals that are used by our brain to transmit information from one brain cell to another. Dopamine is associated with how we feel something is significant, important  or interesting.

It is thought that in people with psychosis, the levels of dopamine in their brain rise too high. The excess dopamine interrupts the specific pathways of the brain responsible for some of its most important functions, such as:

  • memory
  • emotion
  • social behaviour
  • self-awareness

Disruption to these important brain functions may explain the symptoms of psychosis.

Evidence for the role of dopamine in psychosis comes from several sources, including brain scans, and the fact  that medications known to reduce the effects of dopamine in the brain also reduce symptoms of psychosis. However, illegal drugs known to increase the levels of dopamine in the brain, such as cannabis, cocaine and amphetamines, can trigger psychosis.

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You should visit your GP if you are experiencing psychotic episodes. It is important to speak to your GP as soon as possible because early treatment of psychosis usually has  better long-term outcomes.

Visit your GP

There is no test to positively diagnose psychosis. However, your GP will look at your symptoms and rule out short-term causes, such as drug misuse.

Your GP may ask questions to determine the cause of your psychosis. For example, you may be asked:

  • whether you are currently taking any medication
  • whether you have been taking any illegal substances
  • how your moods have been – for example, whether you have been depressed
  • how you have been functioning day-to-day – for example, whether you are still working
  • whether you have a family history of mental health conditions, such as schizophrenia
  • about the details of your hallucinations, such as whether you have heard voices
  • about the details of your delusions, such as whether you feel that people are controlling you
  • whether you have any other symptoms


The evidence supporting the early treatment of psychosis means that you are likely to be referred to a specialist urgently. This will either be during or after your first episode of psychosis. Who you are referred to will depend on what services are available in your health board area. However, you may be referred to:

  • a community mental health team – a team of different mental health professionals who provide support to people with complex mental health conditions
  • a crisis resolution team – a team of different mental health professionals who treat people currently experiencing a psychotic episode, who would otherwise require hospitalisation
  • an early intervention team – a team of mental health professionals who work with people who have experienced their first episode of psychosis

These teams are likely to include some or all of the following healthcare professionals:

  • a psychologist – a healthcare professional who specialises in the assessment and treatment of mental health conditions
  • a psychiatrist – a qualified medical doctor who has received further training in treating mental health conditions
  • a community mental health nurse – a nurse with specialist training in mental health conditions

Your psychiatrist will carry out a full assessment to diagnose any underlying mental health condition that could be causing your symptoms. This will help them when planning your treatment.

Helping others

The lack of self-awareness that is associated with psychosis means that people who are experiencing psychosis will not be able to recognise that they are behaving strangely. They may be reluctant to visit their GP if they believe there is nothing wrong with them, and you may need to get help for them.

Someone who has had psychotic episodes in the past may have been assigned a social worker (someone who works in social services), so try to contact them to express your concerns.

If someone is having a psychotic episode for the first time, it may be necessary for a friend, relative or someone else who is close to them to persuade them to visit their GP. If someone is having a rapidly worsening psychotic episode, contact the duty psychiatrist at their nearest A&E department.

If a person who is having a psychotic episode refuses to seek help, and it is believed to present a risk to themselves or others, their nearest relative can request that a psychological assessment is carried out. The social services department of your local authority will be able to advise you about this.

In severe cases of psychosis, people can be compulsorily detained at hospital for assessment and treatment under the Mental Health Act (1983).

Mental Health Act (1983)

The Mental Health Act (1983) is the main piece of legislation that covers the assessment, treatment and rights of people with a mental health condition. Under the Act, a person can only be compulsorily admitted to hospital or other mental health facility if:

  • they have a mental disorder of a nature or degree that makes admission to hospital appropriate
  • they should be detained in the interests of their own safety or for the protection of others, or both for their safety and other’s protection

Two doctors need to agree on the above assessment. Depending on the nature of the mental health disorder and the individual’s circumstances, the length of time that a person can be sectioned is:

  • 72 hours
  • 28 days
  • 6 months

Before these time periods have elapsed, an assessment will be carried out to determine whether it is safe for the person to be discharged, or whether further treatment is required.

If you are being held under the Mental Health Act (1983), you can be treated against your will because it is felt you do not have sufficient capacity to make an informed decision about your treatment. However, certain treatments, such as brain surgery, cannot be carried out unless you provide your consent.

See consent for treatment for more information on issues such as consent and capacity.

Any person who is compulsorily detained has the right to appeal against the decision to a Mental Health Review Tribunal (MHRT). A MHRT is an independent body that decides whether a patient should be discharged from hospital.

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Treatment for psychosis involves a combination of antipsychotic medicines, and psychological therapies and social support.

Your care team

Your treatment is likely to be co-ordinated by a team of mental health professionals working together. If this is your first psychotic episode, you may be referred to an early intervention team.

Early intervention teams

An early intervention team are teams of healthcare professionals set up specifically to work with people who have experienced their first episode of psychosis.

Some early intervention teams may only focus on a certain age range, such as people who are 14 to 35 years old. Depending on what is necessary for your care, early intervention teams aim to provide:

  • a full assessment of your symptoms
  • prescriptions for medications
  • psychological services
  • social, occupational and educational interventions

Treatment for psychosis will vary depending on the underlying cause  for example, your treatment may be slightly different if you have been diagnosed with an underlying mental health condition as well.

For example:

Psychosis related to drug or alcohol intoxication or withdrawal may only require a short course of antipsychotics or tranquilisers (which have a calming effect). Referral to an addiction counsellor may then be recommended.


Antipsychotic medicines, also known as neuroleptics are usually recommend as the first treatment for psychosis. Antipsychotics work by blocking the effect of dopamine (a chemical that transmits messages in the brain). However, they are not suitable or effective for everyone as side effects can affect people differently.

In particular, antipsychotics will be monitored closely in people who also have:

Antipsychotics can usually reduce feelings of anxiety or aggression within a few hours of use, but they may take several days or weeks to reduce other psychotic symptoms, such as hallucinations or delusional thoughts.

Antipsychotics can be taken orally (by mouth) or given as an injection. There are several 'slow release' antipsychotics, where you only need to have one injection every 2-6 weeks.

Depending on the underlying cause of your psychosis, you may only need to take antipsychotics until your psychosis subsides. However, if you have a condition such as schizophrenia, or bipolar disorder, their long-term use may be recommended in order to prevent further episodes of psychosis.

Side effects

Both typical and atypical antipsychotics have side effects, although not everyone will experience them and their severity will differ from person to person.

Side effects of typical antipsychotics can include:

  • drowsiness which may affect your ability to drive
  • shaking and trembling
  • restlessness
  • muscle twitches and spasms (where your muscles shorten tightly and painfully)
  • blurred vision
  • dizziness
  • constipation
  • loss of libido (sex drive)
  • dry mouth

See the patient information leaflet that comes with your medicine for a full list of possible side effects.

In addition long-term use of antipsychotics can lead to complications such as weight gain and diabetes.

You should tell your GP if side effects are becoming particularly troublesome because there may be an alternative antipsychotic medicine that you can take.

You should never stop taking medication prescribed for you unless you are advised to do so by a qualified healthcare professional responsible for your care. Suddenly stopping prescription medication could trigger a relapse (return) of your symptoms. When it is time for you to stop taking your medication it will be done gradually and under close observation.

Psychological treatment

Psychological treatment, such as counselling, (a talking therapy), can help to reduce the intensity and anxiety caused by psychosis. Some possible psychological treatments are discussed below.

Cognitive behavioural therapy

Cognitive behavioural therapy (CBT) for psychosis is based on an understanding of how people make sense of their experiences and why some people become distressed by them. The aim of CBT is to identify unhelpful thinking patterns and emotions that may be causing your unwanted feelings and behaviours.  It is then possible to replace this thinking with more realistic and balanced thoughts.

A CBT therapist may encourage you to consider different ways of understanding what is happening to you. The aim is to help you achieve goals that are meaningful and important to you, such as reducing your distress, returning to work or university, or regaining a sense of control.

Family therapy

As family therapy is known to be an effective treatment for people with psychosis.

Family therapy is a way of helping both you and your family to cope better with your condition. After experiencing an episode of psychosis, you may rely on your family members for their care and support. While most family members are happy to help, the stress of caring for somebody can place a strain on any family.

Family therapy involves a series of informal meetings that take place over a period of six months. Meetings may include:

  • discussing information about your condition, such as what treatments are available and how your condition might progress
  • exploring ways of supporting someone with psychosis
  • deciding how to solve practical problems that can be caused by psychosis - for example, planning how to manage a future psychotic episode

Self-help groups

If you are experiencing episodes of psychosis, a self-help group can be an additional source of support. You may benefit from being around others who have been through similar experiences. For example the mental health charity, Mind, has a network of local Mind services and you may be able to find a support group in your area.

The Mental Health Act (1983)

If you are experiencing a particularly severe psychotic episode, and it is thought that you present a significant danger to yourself, or others, you can be compulsory detained at hospital or psychiatric clinic under the Mental Health Act (1983).

If you are detained under the Mental Health Act (1983), every effort will be made to try to obtain your consent (agreement) for treatment. However, treatment can be carried out without consent if it is felt that you do not have the mental capacity to understand the issues surrounding treatment.

An independent panel will regularly review your case and your progress. Once they feel that you are no longer a danger to yourself and others, you will be able to leave the hospital or clinic. However, your care team may recommend that you remain in hospital or in the clinic, on a voluntary basis.

Dealing with violence and aggression

Acts of violence and aggression are actually uncommon in people with psychosis. They are more likely to be victims of violence than perpetrators. However, there may be time when your behaviour places yourself or others at risk of harm.

Mental health staff have received special training in dealing with aggressive behaviour.

If you fail to respond to requests to calm down, it may be necessary to hold you down without hurting you. This is known as a physical intervention. You may then be moved to a secluded room to calm down.

In some cases it may be necessary to give you a medication that will cause you to become very relaxed in a short space of time. This is known as rapid tranquillisation.

You will be asked to take the medication voluntarily but if you refuse you can be treated against your consent. This may involve giving you an injection of a tranquiliser.

It should be stressed that the methods described above are only ever used in extreme circumstances and are in no way a routine part of treating psychosis.

Advance decisions

If there is a risk of future psychotic episodes occurring, and there are certain treatments that you do not want to have, it is possible to pre-arrange a legally binding advance decision (previously known as an advance directive).

An advanced decision is a series of written instructions about what you would like your family or friends to do in case you do experience another psychotic episode. You may want to also include the contact details of your care team and social worker.

To create an advance decision, you need to make your wishes clear in writing and have it signed by a witness. You need to include specific details about which treatments you do not want to have, and the specific circumstances in which they may apply.

However, it's important to remember that the advance decision can be overruled if a person is subsequently detained under the Mental Health Act.

Although your doctors will try to take your wishes into account when deciding on treatment, they may decide it's in your best interests not to follow the advance decision.

Reporting side effects

The Yellow Card Scheme allows you to report the suspected side effects of any medicine that you are taking. It is run by a medicines safety watchdog called the Medicines and Healthcare products Regulatory Agency (MHRA). See the Yellow Card Scheme website for more information.


If you have psychosis, it could affect your ability to drive. It is your legal obligation to inform the Driver and Vehicle Licensing Agency (DVLA) about a medical condition that could have an impact on your driving ability. See the GOV.UK website to find out how to tell the DVLA about a medical condition.

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Research has shown that regular cannabis users are 40% more likely to develop a psychotic illness, such as schizophrenia, than people who do not use the drug.

Cannabis is known to increase the levels of dopamine (a chemical that helps transmit messages) in your brain. Therefore, long-term cannabis use may cause permanent changes in your brain's chemistry that could lead to psychosis.

People who regularly use 'skunk' - the herbal type of cannabis which is specifically bred for its increased strength - are thought to be most at risk.

You should also avoid using other recreational drugs, such as cocaine and ecstasy, because they also increase your risk of developing psychosis.

Read more information about drug misuse.

Stress and depression

Experiencing prolonged bouts of stress can sometimes trigger an episode of depression. Both stress and depression are major risk factors for psychosis.

The advice listed below may help to reduce your levels of stress, helpling prevent depression and a subsequent psychotic episodes.

  • Use a problem-solving approach to deal with stresses and worries.
  • Try to identify negative thoughts and change them to positive thoughts.
  • Assess your symptoms regularly and consult your GP or counsellor if problems arise.
  • Take regular exercise. Exercise can trigger the release of the brain chemical serotonin, which boosts your mood. 
  • Learn how to relax using relaxation exercises and tapes.
  • Practice yoga and meditation, or have a massage to help relieve tension and anxiety.
  • Join a self-help group and discuss your feelings and concerns. This can help you to feel less isolated.
  • Avoid smoking, illegal drugs, and drinking alcohol. These may make you feel better in the short-term, but will usually make you feel worse in the long-term.

Read more about depression and stress for more information about these conditions.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 17/09/2014 11:10:48

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