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What is psychosis?

Psychosis is a condition that affects a person’s mind and causes changes to the way that they think, feel and behave. A person who experiences psychosis may be unable to distinguish between reality and their imagination.

People who are experiencing psychosis are referred to a psychotic. People with psychosis often experience:

  • hallucinations - hearing, or seeing, things that are not there, and
  • delusions - believing things that are untrue.

Psychosis is not a condition in itself - it is a symptom of other conditions. The most common cause of psychosis is a mental health condition, such as schizophrenia, or bipolar disorder (manic depression).

Psychosis can also be triggered by physical conditions, such as Parkinson's disease, or as a result of drug or alcohol abuse.

How long someone will experience a psychotic state of mind - known as a psychotic episode - will depend on the underlying causes. Drug, or alcohol, induced psychosis many only last for a few days. However, psychosis that is caused by schizophrenia, or bipolar disorder, may last indefinitely unless it is treated.

How common is psychosis?

Psychosis is more common that most people realise. It is estimated that 1 in every 200 people in the UK has experienced psychosis. Some people will only experience one psychotic episode, while others may experience a number of episodes throughout their life.

Schizophrenia, which is one of the main causes of psychosis, will affect one person in every 100 in the population during their lifetime. 


Prompt treatment is recommended for someone who is experiencing psychosis.  Studies suggest that the earlier the condition is treated, the better the long-term results tend to be. In the short-term, medicines are used to treat the symptoms of psychosis in order that the person is no longer a danger to themselves, or to others. The long-term treatment will depend on the underlying causes.

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. Go to the Directgov website to find out how to tell the DVLA about a medical condition.

'Psychosis' versus 'psychopath'

The term 'psychosis' should not be confused with the term 'psychopath'. The two conditions are very different.

Someone with psychosis has an acute (short-term) condition that, if treated, can often lead to a full recovery.

A psychopath is someone who has an incurable anti-social personality disorder, which means that they lack the capacity for empathy (understanding how someone else feels), are manipulative, and often have a total disregard for the consequences of their actions.

Unlike people with psychosis, people with anti-social personality disorder can appear to act in a rational manner which makes their condition hard to detect.


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

  • hallucinations,
  • delusions,
  • confused and disturbed thoughts, and
  • 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 as outlined below.

  • 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 insects are crawling on the skin.
  • 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 having an unshakable belief in something that is implausible, bizarre or obviously untrue. There are two common types of psychotic delusion that are described below.

  • 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, which in turn 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 - in this type of delusion, a person with psychosis believes that they have some imaginary power, or authority. For example, they may think they are president of a country, or that they 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:

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

Lack of insight

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

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

Postnatal psychosis

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

It is estimated that postnatal psychosis affects one or two women in every 1,000 who give birth, and most commonly occurs during the first month 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, someone with postnatal psychosis may also have thoughts of harming themselves or their baby.


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The causes of psychosis have three main classifications:

  • psychosis caused by psychological (mental) conditions,
  • psychosis caused by general medical conditions, and
  • 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 have 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 (see Psychosis – Symptoms).

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 abnormally low blood sugar (glucose) levels
  • 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) 
  • brain tumour  a growth of cells in the brain that multiply in an abnormal and uncontrollable way


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

Drugs that are known to trigger psychotic episodes include:

  • alcohol,
  • cocaine,
  • amphetamine (speed),
  • methamphetamine (crystal meth),
  • MDMA (ecstasy),
  • cannabis,
  • LSD (acid),
  • psilocybins (magic mushrooms), and
  • ketamine.

Psychosis may also rarely occur as a side-effect of some types of medication, or as a result of an overdose of that medication. These medications include:

  • tranquillisers, such as barbiturates, or benzodiazepines,
  • anti-epileptic medication,
  • antidepressants,
  • anticholinergics medications (medicines that are often used to help open up the airways), and
  • levodopa (a medication used to treat Parkinson's disease).

Never stop taking a prescribed medication unless you are 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.

Grey matter

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

MRI scans carried out on people with a history of psychosis have shown that they tend to have less grey matter than normal. Grey matter is the part of the brain responsible for processing thoughts. MRI scans use a strong magnetic field and radio waves to take images of the inside of the body. This has lead to some researchers suggesting that repeated episodes of psychosis may actually cause physical damage to the brain. However, further research is required to confirm this.

Alternatively, both the reduction of grey matter, and a history of psychosis, could both be symptoms of a yet-unidentified underlying condition.


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 feelings of pleasure and reward. For example, when you experience an enjoyable, or pleasurable, event, such as sex, the levels of dopamine in your brain are increased.

It is thought that in people with psychosis, the levels of dopamine in their brain become too high. The excess dopamine interrupts the specific pathways of the brain that are responsible for some of its most important functions, such as memory, emotion, social behaviour, and self-awareness. The disruption to these important brain functions may explain the symptoms of psychosis.

The evidence for the role of dopamine in psychosis is that medications that are known to reduce the effects of dopamine in the brain also reduce the symptoms of psychosis. Whereas, illegal drugs that are known to increase the levels of dopamine in the brain, such as cannabis, cocaine, and amphetamines, can trigger psychosis.

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Diagnosing psychosis  

Visit your GP if you are experiencing psychotic episodes. It is important to speak to your GP as soon as possible because people who have their psychosis treated early have better long-term outcomes. 

Visit your GP

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

Your GP may ask you a number of questions to try 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 who are 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 (see Psychosis – 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 that 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 that they 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 how to go 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 terms of 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 compulsorily detained for under the Mental Health Act (1983) is:

  • 72 hours
  • 28 days
  • six months

After each of 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.

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.

The Directgov website contains more information about mental health and the Mental Health Act (1983).



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Treatment for psychosis involves using a combination of antipsychotic medicines and psychological therapies.

Your treatment is likely to be co-ordinated by a special team consisting of a variety of mental health professionals working together (see Psychosis - diagnosis). If this is your first psychotic episode, you may be referred to an early intervention team (see below).

Treatment for psychosis will vary depending on the underlying cause - for example, your treatment may be slightly different if you have been diagnosed with another health condition as well. For more information see:

Early intervention teams

If this is your first episode of psychosis, you may be referred to an early intervention team. These 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. However, if one of these teams is available in your area, you will be offered their assistance, if possible.

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

See NHS Mental health services for more information about the different healthcare professionals who may be involved in your treatment and the different services that are available.


Antipsychotics, also known as neuroleptics are usually recommend as the first-line treatment for psychosis. Antipsychotics work by blocking dopamine (a chemical that transmits messages in the brain).  

There are two main types of antipsychotics:

  • typical antipsychotics - the first generation of antipsychotics that were developed during the 1950s, and
  • atypical antipsychotics - a newer generation of antipsychotics that were developed during the 1990s.

Atypical antipsychotics are usually recommended as they have less potential to cause side effects. However, they are not suitable, or effective, for everyone as the side effects can affect people differently. In particular, antipsychotics will be monitored closely in people who also have:

  • epilepsy – a condition that causes seizures or fits
  • cardiovascular disease – a condition that affects the heart, blood vessels or circulation, such as heart disease

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 (as a pill) 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.

The side effects of typical antipsychotics include:

  • drowsiness which may affect your ability to drive,
  • shaking,
  • trembling,
  • restlessness,
  • muscle twitches, and
  • spasms - where your muscles shorten tightly and painfully

Side effects of both typical and atypical antipsychotics include:

  • weight gain,
  • blurred vision,
  • dizziness,
  • constipation – an inability to empty your bowels ,
  • lack of sex drive, and
  • dry mouth.

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

You should never stop taking medication that has been prescribed for you unless you are advised to do so by a qualified healthcare professional who is 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) is based on the assumption that your problems are often created by you. It is not the situation itself that is making you unhappy, but how you think about it and how you react to it.

Most unwanted thinking patterns and emotional and behavioural reactions are learnt over a long period of time. The aim of CBT is to identify the unhelpful thinking that is causing your unwanted feelings and behaviours, and to learn to replace this thinking with more realistic and balanced thoughts.

See the Encyclopaedia A-Z topic about CBT for more information about this type of treatment.

Family therapy

As family therapy is known to be an effective treatment for people with schizophrenia, it is also sometimes used to treat people who have experienced an episode of 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 associations and shops and you may be able to find a support group in your area.

The Mental Health Act

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.

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. 

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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, or ecstasy because these will also increase your risk of developing psychosis.

Stress and depression

Experiencing prolonged bouts of stress can trigger an episode of depression, and both stress and depression are a major risk factor for psychosis.

The advice below may help to reduce your levels of stress, preventing depression and a subsequent psychotic episode.

  • 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 doctor and/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 alcohol. These may appear to make you feel better in the short-term, but they can make you feel worse in the long-term.

See the Encyclopaedia A-Z topics about Depression and Stress for more information about these conditions.


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