Psychosis is when a person loses some contact with reality. They may hear or see things others cannot, or hold strong beliefs that other people do not share. Their thinking and speech may become muddled.
Psychosis is a set of symptoms, not one illness. Causes include schizophrenia, bipolar disorder, severe depression, drugs or alcohol, physical illness, medicines and having a baby.
It is treatable. The HSE says treatment often leads to a full recovery. Both the HSE and the NHS say earlier treatment can be more effective, so speak to a GP as soon as possible.
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In Ireland, phone 112 or 999 or go to an emergency department if someone:
In the UK, call 999 or go to A&E if someone wants to harm themselves or others, hears voices telling them to do harm, is very agitated or aggressive, has hallucinations that are quickly getting worse, or suddenly becomes confused.
Same day: contact a GP or out-of-hours GP. In the UK you can also call NHS 111 and choose the mental health option. If someone already has a mental health team or key worker, contact them.
If you have thoughts of suicide: in Ireland or the UK, freephone Samaritans on 116 123, any time. In Ireland you can also text 50808. In the US, call or text 988, or call 911 in an emergency.
The HSE and NHS describe three main symptoms:
During an episode, the HSE says a person may not realise their experiences are not real. They may feel frightened or distressed. Family and friends may notice the changes first.
Psychosis is not the same as being a "psychopath". The HSE says violence is not common in psychosis. People with psychosis are more likely to harm themselves than others, and more likely to be victims of violence.
The HSE's 2019 model of care for early intervention in psychosis estimates that psychotic disorders affect about 3 in 100 people in their lifetime. Each year in Ireland, about 1,500 people develop one for the first time. Two-thirds of first presentations happen before age 35.
Psychosis can start suddenly or build slowly. Before a first episode of schizophrenia, the HSE says there can be a "prodromal" period of gradual change. It can include:
The HSE notes these signs can be mistaken for normal teenage behaviour. They can also have many other causes.
What matters is a pattern. NICE guidance for England covers people who are distressed and functioning less well socially. If they also have brief or mild psychotic symptoms, it says to refer them without delay. The same applies to other experiences that suggest psychosis, or having a parent, brother, sister or child with psychosis. Referral is to a specialist mental health service or an early intervention team.
The HSE groups causes into mental health conditions, physical health conditions, and substances such as alcohol or drugs. Stress, trauma and lack of sleep can also play a part.
The HSE lists drugs known to trigger psychotic episodes. They include cannabis, cocaine, amphetamine, methamphetamine, mephedrone, MDMA, LSD, magic mushrooms and ketamine.
Psychosis can also happen during withdrawal, sometimes a few weeks after someone suddenly stops long-term use.
The NHS says teenagers and young adults who use cannabis regularly are more likely to develop schizophrenia later. The risk may be higher with stronger forms. It adds that it is not clear whether drugs directly cause symptoms.
A study across 11 sites in Europe and Brazil compared 901 people with a first episode of psychosis with 1,237 local people. Daily cannabis use was linked to about three times the odds of psychosis, compared with never using it. Daily use of high-potency cannabis was linked to nearly five times the odds. This kind of study shows a link. On its own it cannot prove cause and effect.
Postpartum psychosis is rare but serious. The HSE says it affects around 1 in 500 women who give birth. The NHS puts it at around 1 in 1,000 mothers.
Symptoms start suddenly. The HSE says they usually begin within 2 to 3 days of birth but can start any time in the first few weeks. They can include feeling "high", racing thoughts, not wanting to sleep, low mood, confusion, suspicion, hallucinations and delusions.
The risk is highest if you have had it before, or you or a close relative have bipolar disorder. But the HSE says it can happen "out of the blue".
In Ireland, contact your GP, midwife, public health nurse or mental health service urgently, or go to an emergency department. The person may not realise they are unwell, so family may need to act. The Department of Health said in October 2025 that specialist perinatal mental health services cover all 19 maternity hospitals. Our postpartum depression guide explains how this differs from postnatal depression.
Sudden confusion is an emergency. The NHS says a person with sudden confusion (delirium) may see or hear things that are not there. Common causes include infections, stroke, low blood sugar, some medicines and alcohol withdrawal. Call 112 or 999 in Ireland, or 999 in the UK.
Dementia with Lewy bodies. The NHS lists hallucinations among its symptoms. They can range from pleasant to distressing. Read why Lewy body dementia often gets missed.
Parkinson's disease. The NHS says dementia linked to Parkinson's can include visual hallucinations and delusions. It also says Parkinson's medicines called dopamine agonists can cause hallucinations, especially in older people. See our guide to Parkinson's disease treatment. Never stop a Parkinson's medicine without advice.
The HSE says there is no test for psychosis. Your GP will ask about:
It can help to bring someone you trust, and a note of what has changed and when.
Your GP may refer you to a community mental health team (CMHT). This may include a psychiatrist, mental health nurse, psychologist, social worker and occupational therapist.
EIP teams specialise in a first episode of psychosis. The HSE's 2019 model of care covers people aged 14 to 65 with a first episode. It aims to cut delays to treatment and support recovery over the first 3 to 5 years.
These teams do not yet cover the whole country. The Department of Health said in October 2025 that five EIP teams were operational. Three more were being developed with 2025 funding. Budget 2026 funded one further team.
Ask your GP or CMHT whether an EIP team covers your area. Where there is none, care is usually through your local CMHT.
The HSE says treatment usually combines medicine and talk therapy. It depends on the cause.
Antipsychotic medicines are usually the first treatment. The HSE says they can ease distress within hours, but may take days or weeks to reduce hallucinations or delusions.
Side effects can include drowsiness, weight gain, restlessness and shaking. Tell your team if they are a problem. Do not stop suddenly, as symptoms can return. Our explainer on what antipsychotics actually do covers how they differ.
Talk therapies include cognitive behavioural therapy (CBT) for psychosis and family intervention, which helps the whole family cope and plan ahead.
NICE guideline CG178 covers adults in England. It was last updated in September 2026. For a first episode, it recommends:
The NHS says to see a GP immediately, or use NHS 111. You may be referred urgently to a community mental health team, crisis team or early intervention team. NICE says early intervention services should be open to anyone with a first episode, whatever their age. A NICE quality standard says adults should start treatment there within 2 weeks of referral.
In England and Wales, a person with very severe psychosis who is a danger to themselves or others can be detained under the Mental Health Act 1983.
The HSE suggests:
If someone is at immediate risk, phone 112 or 999. The HSE describes involuntary admission as a last resort. Shine also supports families.
Many people recover fully. Others have further episodes, and treatment can reduce their impact.
Stigma is a real barrier to help. The Irish Psychosis Survey 2024 heard from 378 people with lived experience of psychosis and their supporters. Over 70% found media portrayals of psychosis inaccurate, and 54% reported stigma at work. It was run by Shine, Mental Health Reform and the HSE's EIP programme.
Words matter. Say "a person with psychosis", not labels such as "psychotic", "psycho" or "crazy".
The NHS says people with psychosis have a higher than average risk of self-harm and suicide. In Ireland or the UK, freephone Samaritans on 116 123. In Ireland you can also text 50808. In an emergency, call 112 or 999 in Ireland, or 999 in the UK.
No. Schizophrenia is one cause. Psychosis can also come with bipolar disorder, severe depression, drug use, physical illness or childbirth. A psychiatrist works out the cause.
The HSE lists cannabis among drugs known to trigger psychotic episodes. Research links regular and high-potency use with higher odds of psychosis. If you have had psychosis, the NHS says drug use can cause a relapse.
Yes. The HSE says treatment often leads to a full recovery. Some people have further episodes, and early treatment helps.
The HSE lists stress, trauma and lack of sleep among possible causes, often alongside other factors. Anyone with symptoms should see a GP promptly.
This article is general information, not medical advice. It cannot diagnose psychosis or its cause. Talk to your GP about your own symptoms, and before starting, stopping or changing any medicine.
Reviewed by: Proco Team
Last updated: November 2026