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 – for example, thinking your next door neighbour is planning to kill you

The combination of hallucinations and delusional thinking can often severely disrupt perception, thinking, emotion, and behaviour.

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

What causes psychosis?

Psychosis isn't a condition in itself – it's triggered by other conditions.

It's sometimes possible to identify the cause of psychosis as a specific mental health condition, such as:

  • schizophrenia – a condition that causes a range of psychological symptoms, including hallucinations and delusions
  • 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 recur.

Read more about the causes of psychosis.

Diagnosing psychosis

You should see your GP immediately if you're experiencing psychotic episodes. It's important psychosis is treated as soon as possible as 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.

Read more about diagnosing psychosis.

Treating psychosis

Treatment for psychosis involves using a combination of:

  • antipsychotic medication – which can help relieve the symptoms of psychosis
  • psychological therapies – the one-to-one talking therapy cognitive behavioural therapy (CBT) has proved successful in helping people with schizophrenia; in appropriate cases, family therapy has been shown to reduce the need for hospital treatment in people with psychosis
  • social support – support 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 recurring.

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 a lack of insight. They're unaware that they're thinking and acting strangely.

Because of their lack of insight, it's often down to the friends, relatives, or carers of a person affected by psychosis to seek help for them.

If you're concerned about someone you know and think they may have psychosis, you could contact their social worker or community mental health nurse if they've previously been diagnosed with a mental health condition. If you think the person's symptoms are placing them at possible risk of harm, you can:

  • take them to the nearest accident and emergency (A&E) department, if they agree
  • call their GP or local out-of-hours GP
  • call 999 and ask for an ambulance


People with a history of psychosis are much more likely to have drug or alcohol misuse problems, or both.

This may be because these substances can provide short-term symptom relief, although they usually make symptoms worse in the long term.

People with psychosis also have a higher than average risk of suicide. It's estimated 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 someone is 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.

Read more about the complications of psychosis.


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

However, four main symptoms are associated with a psychotic episode. They are:

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

These are outlined in more detail below.


Hallucinations are where a person perceives something that doesn't exist in reality. They can occur in all five of the senses:  

  • sight – someone with psychosis may see colours and shapes, or people or animals that aren't there
  • 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 nobody there
  • smell – usually a strange or unpleasant odour
  • taste – some people with psychosis have complained of having a constant unpleasant taste in their mouth


A delusion is where a person has an unshakeable belief in something implausible, bizarre, or obviously untrue. Paranoid delusion and delusions of grandeur are two examples of psychotic delusions.

A person with psychosis will often believe 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 mind control devices.

Someone with psychosis may also have delusions of grandeur. This is where they believe they have some imaginary power or authority. For example, they may think they're the president of a country or they have the power to bring people back from the dead.

Confused and disturbed thoughts

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

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

Lack of insight

People who have psychotic episodes are often totally unaware their behaviour is in any way strange or that their delusions or hallucinations are not real.

They may recognise delusional or bizarre behaviour in others, but lack the self-awareness to recognise it in themselves.

For example, a person with psychosis being treated in a psychiatric ward may complain that their fellow patients are mentally unwell, while they're 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 having a baby.

It's estimated postnatal psychosis affects around 1 in every 1,000 women who give birth. It most commonly occurs during the first few weeks after having a baby.

Postnatal psychosis is more likely to affect women who already have a mental health condition, such as bipolar disorder or schizophrenia

As well as the symptoms of psychosis, symptoms of postnatal psychosis can also 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 a medical emergency. Contact your GP immediately if you think someone you know may have developed postnatal psychosis. If this isn't possible, call the NHS 24 '111' service or your local out-of-hours service.

If you think there's an imminent danger of harm, call 999 and ask for an ambulance.


The causes of psychosis have three main classifications.

They are psychosis caused by:

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

The 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 long-term (chronic) mental health condition that causes hallucinations and delusions
  • bipolar disorder – a condition that affects a person's moods, which can swing from one extreme to another (highs and lows)
  • severe stress or anxiety
  • severe depression – feelings of persistent sadness that last for more than six weeks, 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 someone experiences.

For example, a person with bipolar disorder is more likely to have delusions of grandeur, whereas someone with depression or schizophrenia is more likely to develop paranoid delusions.

General medical conditions

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

  • HIV and AIDS – a virus that attacks the body's natural defence against illness and infection (the immune system)
  • malaria – a tropical disease spread by infected mosquitoes
  • syphilis – a bacterial infection usually passed on through sexual contact
  • Alzheimer's disease – the most common form of dementia, which causes a decline in mental abilities like memory and reasoning
  • Parkinson's disease – a long-term 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 the immune system attacks healthy tissue
  • Lyme disease – a bacterial infection spread to humans by infected ticks
  • multiple sclerosis – a condition that affects the nerves in 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 misuse and drug misuse can trigger a psychotic episode.

A person can also experience a psychotic episode if they suddenly stop drinking alcohol or taking drugs after using them for a long time. This is known as withdrawal.

It's also possible to experience psychosis after drinking large amounts of alcohol or if you're high on drugs.

Drugs known to trigger psychotic episodes include:

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

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

For example, levodopa, a medication used to treat Parkinson's disease, can sometimes cause psychotic episodes. However, 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 responsible for your care.

See your GP if you're experiencing psychotic side effects caused by medication.

The brain

There's been a great deal of research into how psychosis affects the brain and how changes in the brain can trigger symptoms of psychosis.

Grey matter

Research has revealed several physical and biological changes occur in the brain during a psychotic episode. Grey matter is the part of the brain responsible for processing thoughts.

The results of magnetic resonance imaging (MRI) scans have shown some people with a history of psychosis have less grey matter than most other people. However, it's not yet fully understood why this is.


Researchers also believe dopamine plays an important role in psychosis.

Dopamine is a neurotransmitter, one of many chemicals the brain uses to transmit information from one brain cell to another. It is associated with how we feel whether something is significant, important, or interesting.

It's thought levels of dopamine in the brain become too high in people with psychosis. The excess dopamine interrupts specific pathways in the brain that are 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 medications known to reduce the effects of dopamine in the brain also reduce the symptoms of psychosis.

However, illegal drugs known to increase levels of dopamine in the brain – such as cannabis, cocaine and amphetamines – can trigger psychosis.


You should visit your GP if you're experiencing psychotic episodes.

It's important to speak to your GP as soon as possible as the early treatment of psychosis usually has better long-term outcomes. 

Initial assessment

There's 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, they may ask you:

  • whether you're taking any medication
  • whether you've been taking illegal substances
  • how your moods have 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 the details of your hallucinations, such as whether you've heard voices
  • about the details of your delusions, such as whether you feel people are controlling you
  • about any other symptoms you have


The evidence supporting the early treatment of psychosis means you're likely to be referred to a specialist urgently. This will either be during or after your first episode of psychosis.

Who you're referred to will depend on the services available in your area. 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 help identify and diagnose any underlying mental health condition that could be causing your symptoms. This will help when planning your treatment for psychosis.

Helping others

The lack of insight associated with psychosis means people experiencing it aren't always able to recognise their strange behaviour.

They may be reluctant to visit their GP if they believe there's 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 mental health worker, who works in social services, so try to contact them to express your concerns.

Someone who is having a psychotic episode for the first time may need a friend, relative or someone else close to them to persuade them to visit their GP.

If they're having a psychotic episode that's rapidly getting worse, you should contact their crisis team or, if the team isn't available, the duty psychiatrist at their nearest accident and emergency (A&E) department.

If a person who is having a psychotic episode refuses to seek help and is believed to present a risk to themselves or others, their nearest relative can request a psychological assessment. Your local mental health trust can advise you about this.

If someone has very severe psychosis, they can be compulsorily detained at hospital for assessment and treatment under the Mental Health (Scotland) Act 2015.


Treatment for psychosis involves a combination of antipsychotic medicines, 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 is a team of healthcare professionals set up specifically to work with people who have experienced their first episode of psychosis.

Some early intervention teams only focus on a certain age range, such as people who are 14 to 35 years old.

Depending on your care needs, 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. You'll receive specific treatment if you've been diagnosed with an underlying mental health condition as well.

For example, treatment for bipolar disorder uses a variety of medications, which could include antipsychotics to treat symptoms of mania, lithium and anticonvulsants to help stabilise mood, as well as psychological therapy, such as cognitive behavioural therapy (CBT).

Treatment for schizophrenia usually involves a combination of antipsychotic medication and social support. CBT or another type of psychotherapy called family therapy are also often used. 

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


Antipsychotic medicines, also known as neuroleptics, are usually recommended as the first treatment for psychosis. They work by blocking the effect of dopamine, a chemical that transmits messages in the brain.

However, they're 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 epilepsy, a condition that causes seizures or fits.

People who have cardiovascular disease – conditions that affect the heart, blood vessels, or circulation, such as heart disease – will also be closely monitored.

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 by mouth (orally) or given as an injection. There are several slow-release antipsychotics, where you only need one injection every two to six 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 like schizophrenia or bipolar disorder, you may need to take antipsychotics on a long-term basis to prevent further episodes of psychosis.

Side effects

Antipsychotics can have side effects, although not everyone will experience them and their severity will differ from person to person.

Side effects can include:

  • drowsiness – this 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 sex drive (libido)
  • 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 like weight gain and diabetes.

Read more about the complications of psychosis.

Tell your GP if you have side effects that are becoming particularly troublesome. There may be an alternative antipsychotic medicine you can take.

Never stop taking medication prescribed for you unless advised to do so by a qualified healthcare professional responsible for your care.

Suddenly stopping prescription medication could trigger a return of your symptoms (relapse). When it's time for you to stop taking your medication, it will be done gradually and under close observation. 

Psychological treatment

Psychological treatment can help 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's then possible to learn to replace this thinking with more realistic and balanced thoughts.

A CBT therapist may encourage you to consider different ways of understanding what's 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

Family therapy is known to be an effective form of treatment for people with psychosis. It's a way of helping both you and your family cope with your condition.

After having an episode of psychosis, you may rely on your family members for 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 your condition and how it might progress, plus the available treatments  
  • exploring ways of supporting someone with psychosis 
  • deciding how to solve practical problems caused by psychosis, such as planning how to manage future psychotic episodes 

Self-help groups

If you're experiencing episodes of psychosis, you may benefit from being around other people who've had similar experiences.


Someone experiencing a psychotic episode may self-harm. Suicidal thoughts and an increased risk of suicide are also common.


Self-harming behaviour is a relatively common complication in people with psychosis. A study found 1 in 10 people with psychosis also had a history of self-harm.

The risk of self-harm is thought to be highest in people who are experiencing their first episode of psychosis but aren't receiving treatment.

See your GP if you're self-harming. You can also call the Samaritans on 08457 90 90 90 for support.

If you think a friend or relative is self-harming, look out for signs of unexplained cuts, bruises or cigarette burns, usually on the wrists, arms, thighs, and chest. People who self-harm may keep themselves covered up at all times, even in hot weather. 

A person who's self-harming may feel deep shame and guilt, or they may feel confused and worried by their own behaviour. It's important to approach them with care and understanding.

They may not want to discuss their self-harming behaviour with you, but you could suggest they speak to their GP or a counsellor on a support helpline.


People with psychosis also have an increased risk of suicide. It's estimated 1 in 5 people with psychosis will attempt suicide at some point in their life, and 1 in 25 people with psychosis will kill themselves.

If you're feeling suicidal, you can:

  • call the Samaritans support service on 08457 90 90 90
  • go to your nearest accident and emergency (A&E) department and tell the staff how you're feeling
  • contact the NHS 24 '111' service
  • speak to a friend, family member, or someone you trust
  • make an urgent appointment to see your GP, psychiatrist, or care team

Read more about getting help if you're feeling suicidal.

If you're worried that someone you know may be considering suicide, recommend that they contact one or more of the organisations above and encourage them, in a non-judgemental way, to talk about how they're feeling.

If the person has previously been diagnosed with a mental health condition, such as depression, you can speak to a member of their care team for help and advice.

Read more about the warning signs of suicide and supporting someone who's feeling suicidal.


Using antipsychotics on a medium- to long-term basis can cause a number of complications. Some of the more common complications are discussed below.

Weight gain

Weight gain is a complication of many commonly used antipsychotics. There are two main reasons why weight gain is thought to occur.

Antipsychotics can:

  • lead to an increase in appetite
  • make you less active  

You'll probably be advised to take more exercise to help burn off the excess fat.

Read about getting started with exercise and how to lose weight safely.

Metabolic syndrome

Metabolic syndrome is a term describing a number of related conditions linked to weight gain, such as:

These health conditions can also increase your risk of developing type 2 diabetes, heart disease and, most seriously, heart attack or stroke.

Because of the risk of metabolic syndrome, you'll usually need to have regular blood tests and blood pressure tests while taking antipsychotics.

If your test results show you have an increased risk of developing a condition such as heart disease, a number of preventative treatments, such as statins, are available to help lower cholesterol levels.

Tardive dyskinesia (TD)

Tardive dyskinesia (TD) is another common complication of long-term antipsychotic use.

TD is a movement disorder where a person experiences involuntary movements, such as twitching, tics, grimaces, tremors, and spasms. It usually starts in the face and mouth before spreading to the rest of the body.

In some cases, stopping taking an antipsychotic will provide relief from TD symptoms, but in other cases it makes the symptoms worse.

However, stopping medication isn't always safe and has to be balanced against the risk of having a relapse.

In some cases, TD can be a permanent condition.

There are also a number of treatments that can sometimes improve the symptoms of TD, including:

  • clonazepam – a medication used to treat epilepsy, a condition that affects the brain and causes seizures or fits
  • vitamin E supplements – check with the doctor in charge of your care before taking vitamin supplements as they're not safe or suitable for everyone

Last updated:
03 May 2023