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Knowledge Base » Mental Health » What is Psychosis?

What is Psychosis?

Last updated on 18th April 2023

NHS England states that mental health problems represent the biggest single cause of disability in the UK, with one in four adults experiencing at least one diagnosable mental health condition in any given year. Psychotic disorders, including schizophrenia, are major mental illnesses.

Psychosis is a change of the normal functioning of the brain when people lose some contact with reality. This might involve seeing or hearing things that other people cannot see or hear (this is called having hallucinations); and/or believing things that are not actually true (this is called having delusions); and/or experiencing disorganised thinking and speech.

Psychosis may also be called a “psychotic experience” or “psychotic episode”. Psychosis can affect people in different ways: a person may experience it just once, or have short episodes throughout their life, or live with it most of the time.

Psychosis can be a symptom of some of the more severe forms of mental health problems, such as bipolar disorder, schizophrenia, substance abuse or some forms of personality disorder.

How common is psychosis?

According to the National Institute for Health and Care Excellence (NICE) the estimated prevalence of psychosis across all ages and populations in the UK is 0.7%. In the UK the lifetime prevalence of schizophrenia and psychotic-related disorders is approximately 14.5 per 1,000 people, although there is considerable variation between estimates.

According to the Office for National Statistics (ONS), the prevalence of all mental health disorders in children aged between 5 and 16 years is 9.6% and they reported that the prevalence of psychotic disorders in children aged between 5 and 18 years was 0.4%. Onset of psychosis tends to occur between the ages of 15 and 35 years, which are also the ages when other major mental disorders first present, although younger children can develop the condition.

Woman suffering with postnatal psychosis

What causes psychosis?

As with many mental health issues, the exact causes of psychosis are not well understood but they might involve:

  • Brain changes – Tests have found differences in brain chemicals, specifically the activity of the neurotransmitter dopamine in people who experience 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 and whether something is significant, important or interesting. Disruption to these important brain functions may explain the symptoms of psychosis.
  • Hormones – Due to this, and the fact that the early signs of psychosis often occur first in adolescents, it has led some experts to suggest that hormonal factors may play a role in those with a genetic susceptibility. Some women experience postnatal psychosis after giving birth. Postnatal psychosis is also called puerperal or postpartum psychosis; it is a severe form of postnatal psychosis, a type of depression that some women experience after having a baby. It is estimated that this affects around 1 in every 1,000 women who give birth and 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.
  • Genetic factors – Research shows that schizophrenia and bipolar disorder may share a common genetic cause with psychosis:
    Schizophrenia is a mental health condition that causes hallucinations and delusions.
    – Bipolar disorder – a person with bipolar disorder can have episodes of low mood (depression) and highs or elated mood (mania).
  • Severe stress or anxiety can cause psychosis.
  • Severe depression, that is feelings of persistent sadness and/or extreme low mood, can cause psychosis.
  • A lack of sleep may also trigger psychosis.
  • Alcohol misuse and drug misuse can trigger a psychotic episode. Drugs known to trigger psychotic episodes include:
    – Cocaine.
    – Amphetamine (speed).
    – Methamphetamine (crystal meth).
    – Mephedrone (MCAT or miaow).
    – MDMA (ecstasy).
    – Cannabis.
    – LSD (acid).
    – Psilocybin (magic mushrooms).
    – Ketamine.
  • In rare situations, psychosis can also occur as a side effect of some types of medicine or as a result of an overdose of that medicine.
  • Medical conditions have also been known to trigger psychotic episodes in some people, for example:
    – HIV and AIDS.
    – Malaria.
    – Syphilis.
    – Alzheimer’s disease.
    – Parkinson’s disease.
    – Hypoglycaemia (an abnormally low level of glucose in the blood).
    – Lupus.
    – Multiple sclerosis.
    – Brain tumour.
A man having hallucinations

What are the signs and symptoms of psychosis?

The NHS identifies three main symptoms that are associated with a psychotic episode:

  • Hallucinations – The person hears, sees, smells, tastes or feels things that do not exist, for example:
    – Sight – Seeing colours, shapes or people.
    – Sounds – Hearing voices or other sounds.
    – Touch – Feeling touched when there is nobody there.
    – Smell – An odour that other people cannot smell.
    – Taste – A taste when there is nothing in the mouth.

Auditory hallucinations appear to be the most common where the person hears things and believes them to be real when they do not exist. Often, the person hears voices. There may be one or many voices, and they will sound exactly like real voices.

The voices may:

– Be recognisable, non-specific or of someone who has died.
– Sound either clear or like mumbling in the background.
– Give instructions or criticise the person.
– Be intermittent or constant.

Hearing voices can be very confusing, and it can affect a person’s actions. It can lead to the individual harming themselves or, less often, others.

  • Delusions – The individual believes things that are false, and they may have unfounded fears or suspicions, for example:
    – A person with persecutory or paranoid delusions may believe an individual or organisation is making plans to hurt or to kill them; they may also believe that they are in trouble and that someone is chasing them.
    – A person with grandiose delusions may believe they have power or authority; they may think they are the president or king or queen of a country or that they have the power to bring people back from the dead.
  • Confused and disturbed thoughts, or speech or behaviours for example:
    – Rapid and constant speech.
    – Disturbed speech – They may switch from one topic to another mid-sentence, their speech may make no sense to others.
    – A sudden loss in their train of thought, resulting in an abrupt pause in conversation or activity.
    – Making connections that appear illogical to other people.

A person may not be aware that they have psychosis because the hallucinations and/or delusions feel real to them. Psychosis can be overwhelming and very confusing.

Other medical sources cite additional signs and symptoms such as:

  • Catatonia – The person may become unresponsive.
  • Unusual psychomotor behaviour – The person makes unintentional movements, such as pacing, tapping and fidgeting.
  • Mood changes.
  • Difficulty focusing.

The mild, early signs and symptoms of psychosis might include:

  • General anxiety.
  • Depression.
  • Social isolation.
  • Problems focusing.
  • Mild or moderate disturbances in language, energy levels and thinking.
  • Difficulty taking initiative.
  • Lower tolerance to stress.
  • Sleep problems.
  • Neglecting self-care.
  • Feelings of suspicion.
  • Thoughts and ideas that seem strange to others.
Sleep problems can be an early sign of psychosis

What are the different types of psychosis?


This is the most common psychotic disorder. People with this condition experience changes in behaviour, delusions and hallucinations that last longer than six months. Those diagnosed with this type of disorder often show a decline in social function, and negative effects on school and work.

Schizoaffective Disorder

This is a chronic mental health condition characterised primarily by symptoms of schizophrenia, such as hallucinations or delusions, and symptoms of a mood disorder, such as mania and depression.

Schizophreniform Disorder

Like schizophrenia, this is a psychotic disorder that affects how a person acts, thinks, relates to others, expresses emotions and perceives reality. Unlike schizophrenia, it lasts one to six months instead of the rest of their life.

Brief Psychotic Disorder

This is a sudden, short-term display of psychotic behaviour, such as hallucinations or delusions, which occurs with a stressful event. People with this illness have a sudden, short period of psychotic behaviour and recovery is often quick, usually less than a month.

Delusional Disorder

Previously called paranoid disorder, this is a type of serious mental illness also called a “psychosis” in which a person cannot tell what is real from what is imagined. The main feature of this disorder is the presence of delusions, which are unshakeable beliefs in something untrue.

Substance-Induced Psychotic Disorder

This is a mental health condition in which the onset of the psychotic episodes or psychotic disorder symptoms can be traced to starting or stopping using alcohol or a drug. It can be onset during intoxication or onset during withdrawal.

Psychotic Disorder due to a medical condition

This diagnosis is made when a person’s medical history, physical examination or laboratory test results suggest that one or more medical conditions have caused brain changes that might create psychotic symptoms. Those delusions or hallucinations are happening because of the medical condition(s) such as a brain tumour.


Is a type of mental disorder characterised by paranoid delusions. The affected individual experiences imaginary fears or anxieties that are often exaggerated, but they do not undergo significant loss of intellectual capabilities, such as memory and daily routine habits. Although paraphrenia presents symptoms similar to schizophrenia, it often occurs only in the elderly, above the age of 60, and is also quite a rare condition.

Shared Psychotic Disorder (also called folie à deux)

This illness happens when one person in a relationship has a delusion and the other person in the relationship adopts it, too.

Stress can lead to further problems

What mental health conditions are linked to psychosis?

Many of the other conditions that are linked to psychosis are listed above, however, the word psychosis is usually used to refer to an experience. It is a symptom of certain mental and physical health problems rather than a diagnosis itself. People suffering from severe depression or bipolar disorder may also experience psychosis or psychotic episodes.

Psychosis can also result from other disorders, such as:

  • A brain tumour or cyst.
  • Dementia, including Alzheimer’s disease.
  • Neurological conditions, such as Parkinson’s disease and Huntington’s disease.
  • HIV and other infections that can affect the brain.
  • Some types of epilepsy.
  • Malaria.
  • Syphilis.
  • Stroke.
  • Low blood sugar.
  • Multiple sclerosis (MS).
  • Stress.

Can psychosis be prevented?

The short answer to this is No. But the sooner treatment starts, the better, as it helps to prevent symptoms. Seeking help as soon as possible can help the person’s quality of life, family and relationships. For people who are at high risk of psychotic disorders, such as those who have a family history of schizophrenia, avoiding drugs such as marijuana and alcohol may help to prevent or delay these conditions.

An impending psychotic break can be identified and prevented if it is recognised early and appropriate steps are taken to head it off. If a person is considered to be at increased risk of developing psychosis, medical practitioners may offer individual cognitive behavioural therapy (CBT) with or without family intervention.

NICE recommends that medical professionals do not offer antipsychotic medication:

  • To people considered to be at increased risk of developing psychosis.
  • With the aim of decreasing the risk of or preventing psychosis.

NICE also recommends that early intervention in psychosis services should be accessible to all people with a first episode or first presentation of psychosis, irrespective of the person’s age or the duration of untreated psychosis. They also state that antipsychotic medication should not start for a first presentation of sustained psychotic symptoms in primary care unless it is done in consultation with a consultant psychiatrist.

Early intervention appears to be the key, according to the Mental Health Foundation. For every £1 spent on early intervention psychosis teams (EIP) that work with young people in their first episode, £18 is saved on further interventions not being required.

Girl in a GP appointment discussing symptoms of psychosis

Diagnosing psychosis

There is no test to positively diagnose psychosis. If you are experiencing symptoms of psychosis, visit your GP. The sooner you visit your GP, the more likely it is that treatment will be effective.

Your GP will ask about your symptoms and possible causes. For example, they may ask you:

  • Whether you are taking any medicines and what they are.
  • Whether you have been taking illegal substances, and if so, what.
  • Whether you have been depressed and how your mood has been in general.
  • Whether you are still working or attending school or college and how you have been functioning on a day-to-day basis.
  • Whether you have a family history of mental health conditions, such as schizophrenia.
  • About the details of any hallucinations you may have experienced, such as whether you have heard or are hearing voices.
  • About the details of any delusions you may have experienced, such as whether you feel people are controlling you.
  • About any other symptoms you have.

Following this consultation, if your GP thinks that you may have psychosis you will be referred to a specialist such as a:

  • Community mental health team (CMHT).
  • Crisis resolution team.
  • Early intervention team (EIT).

They will carry out a full assessment to help identify any underlying mental health conditions which could be causing your symptoms. This will allow for the best planning of your treatment.

Treatments available for someone with psychosis

The good news is that psychosis is a treatable condition. If this is your first psychotic episode, you may be referred to an early intervention team. 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.

Before you start any treatment, your mental health professionals should discuss all your options with you and listen to what you want. They should look at all aspects of your life including your environment, culture and ethnicity, and any possible physical causes of your psychosis.

Your treatment may depend on whether you are diagnosed with a specific mental health problem because it may be that psychosis is one of several symptoms you are experiencing, and this will influence what treatment you are offered.

Most psychotic disorders are treated with a combination of psychotherapy and medication, for example:

Talking therapies

These can help you understand your experiences and develop coping strategies to deal with them. You may be offered specific cognitive behavioural therapy for people experiencing psychosis, sometimes called CBT.

Arts therapies

These can help you express how you are feeling in different ways. They can be helpful if you are having difficulty talking about your experience.

Family intervention

This focuses on helping family members talk to each other about what helps, problem solving and planning for a crisis. Your GP will be able to find out if this is available in your area.

Antipsychotic medicines

These may be prescribed, 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 epilepsy, a condition that causes seizures or fits. 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.
  • Shaking and trembling.
  • Dry mouth.
  • Weight gain.
  • Restlessness.
  • Muscle twitches and spasms.
  • Blurred vision.
  • Dizziness.
  • Constipation.
  • Loss of libido.

You may also be offered antidepressants or medications to help with the side effects of the antipsychotics.

Self-help groups

If you are experiencing episodes of psychosis, you may benefit from being around other people who have had similar experiences. The mental health charity Mind has more than 150 local Mind networks.

People at a self-help group to try help each other

Dealing with the symptoms of psychosis

Whilst therapies and medication should provide better control over the symptoms of psychosis, there are additional strategies to help you deal with the symptoms by engaging in an activity that will distract you.

For example:

  • Watching TV.
  • Listening to music.
  • Talking with a family member or friend.
  • Exercise such as cycling, swimming, running.
  • Using a relaxation technique.

You should also reduce your use of drugs and alcohol and eat and sleep well. It might be helpful to keep a diary of things that might have triggered a psychotic experience.

Such as:

  • Life events.
  • Your mood.
  • Your diet.
  • Lack of sleep.

You could do this in a notebook or use an app or online tool. Keeping a diary can help you:

  • Understand what triggers your psychosis or makes it worse.
  • Think about what has been helpful in the past.
  • Recognise warning signs that tell you when you are becoming unwell.

Once you have a better understanding of your triggers, you can try to take steps to avoid or manage them. If you learn to recognise your warning signs, you can take action early to try and prevent your psychosis getting worse.

For family and friends of someone experiencing psychosis, it can help if your loved one feels able to discuss their feelings and options with someone supportive and calm. Listen to their experiences and ask them what would help them.

In conclusion

As we have seen, psychosis is a treatable condition, however, for people experiencing it and for friends and family of sufferers it may be distressing. It may be helpful to have access to additional support and information.

To help you manage the condition, here are some useful contacts:

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About the author

Evie Lee

Evie Lee

Evie has worked at CPD Online College since August 2021. She is currently doing an apprenticeship in Level 3 Business Administration. Evie's main roles are to upload blog articles and courses to the website. Outside of work, Evie loves horse riding and spending time with her family.

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