Psychosis: symptoms, causes and treatment

Key points

• Psychosis is a set of experiences, not a diagnosis in itself. It occurs in several mental health conditions, and in physical illness, brain injury and drug use [2].
• The main experiences are hallucinations, delusions and disorganised thinking [1].
• People experiencing psychosis are far more likely to be harmed than to harm anyone else [4].
• In England, Early Intervention in Psychosis treatment should start within two weeks of referral [6].
• NICE recommends antipsychotic medication and psychological therapy together, not medication alone [5].

What psychosis is

Psychosis is a set of experiences in which a person perceives or interprets things differently from those around them: hallucinations, delusions, and confused or disorganised thinking [1]. Psychosis is not a diagnosis in itself. It occurs in several mental health conditions, and also in physical illness, brain injury, drug use and as a rare effect of some medicines [2].

If you need help now. Samaritans: call 116 123, free, 24/7. Shout: text SHOUT to 85258. NHS 111, then choose the mental health option. Call 999 if anyone is in immediate danger.

The media picture is one of danger to others. The evidence is the opposite: violence is uncommon in people with psychosis, and they are more likely to be victims of violence than to be violent [4].

Psychotic disorders are uncommon: 0.4% of adults in England met the criteria in the past year in 2023/24, and 0.5% across the 2007, 2014 and 2023/24 surveys combined [7].

Symptoms

Psychosis usually builds over weeks, not overnight.

• Hallucinations. Hearing, seeing, smelling, tasting or feeling something other people do not [1]. Hearing voices is the most common form.
• Delusions. Strongly held beliefs others do not share, which do not shift when the person is given evidence against them [1]. Common themes are that others intend harm, or that the person has special powers.
• Confused thinking and speech. Speech that is fast, jumps between subjects or stops suddenly, and trouble concentrating [1].

Commonly confused with. Severe sleep loss, which can produce similar experiences on its own [2]. Delirium during physical illness. The effects of drugs, or of stopping drugs or alcohol suddenly [2].

Types

Psychosis is grouped by what is causing it, rather than by subtypes of its own.

• Schizophrenia. Psychotic experiences over a longer period, with withdrawal and reduced motivation.
• Bipolar disorder. Psychosis during a manic or depressive episode. Beliefs about special powers are more common in mania [2].
• Severe depression. Psychosis fits the low mood: beliefs about guilt, poverty or illness.
• Schizoaffective disorder. Psychotic experiences alongside significant mood episodes.
• Postpartum psychosis. Around 1 in 1,000 women after childbirth. It comes on quickly and is a medical emergency [1].
• Drug-induced psychosis. Cannabis, cocaine, amphetamines, MDMA, LSD and ketamine can trigger an episode, as can stopping alcohol or drugs suddenly [2].
• Physical illness, delirium and brain injury. Infections, dementia, Parkinson’s disease, multiple sclerosis, low blood sugar, brain tumours, head injury, and delirium during acute illness [2].
• A medicine effect. Rare. No prescribed medicine should be stopped without speaking to a prescriber [2].

Causes and risk factors

There is no single cause, and most people with these risk factors never develop psychosis.

• Family history. A close relative with psychosis or schizophrenia raises the risk, and NICE treats it as a reason to refer [5].
• Brain chemistry. Raised neurotransmitter activity, particularly dopamine, appears to be involved, and medicines that reduce dopamine activity reduce symptoms [2].
• Cannabis. Across Europe, daily use was associated with around three times the odds of a psychotic disorder, and daily high-potency cannabis with around five times [10]. The evidence is observational and cannot prove cause.
• Stress, trauma and sleep loss. Severe stress, anxiety, depression and prolonged lack of sleep can all trigger episodes [2].

Psychosis is not a split personality, and it is not caused by bad parenting.

How it is diagnosed

There is no blood test or scan that confirms psychosis [3]. A GP is usually the first step, asking about the experiences, mood, medicines, drug and alcohol use and family history, and arranging tests to look for a physical cause [3]. The diagnosis is made by a psychiatrist registered with the GMC or another specialist mental health clinician [3].

NICE says anyone who is distressed and declining socially, and who has brief or mild psychotic symptoms or a close relative with psychosis, should be referred for assessment without delay [5]. Early Intervention in Psychosis (EIP) services should be open to everyone with a first episode, whatever their age and however long they have been unwell [5]. In England, treatment should start within two weeks of referral, for ages 14 to 65 [6].

The gap between symptoms starting and treatment beginning is the duration of untreated psychosis, which NHS England says strongly influences long-term outcomes [6]. A review of 34 studies found longer untreated psychosis linked to worse functioning and more severe negative symptoms at follow-up, although studies define “long” very differently [9].

NHS records in England are coded to ICD-10, and a first diagnosis is often provisional.

Treatment

NICE recommends that a first episode is treated with oral antipsychotic medication and psychological therapy together, through an EIP service [5].

• Antipsychotic medication. Chosen jointly by the person and the clinician after discussing likely effects, including weight gain, diabetes risk, movement effects and heart effects [5]. Symptoms take days or weeks to settle [4].
• Cognitive behavioural therapy for psychosis (CBTp). One to one, over at least 16 planned sessions [5].
• Family intervention. At least 10 planned sessions, over three months to one year [5].
• Clozapine. Offered when the illness has not responded adequately to at least two different antipsychotics [5].
• Supported employment. Offered to people who want to find or return to work [5].

A meta-analysis of 10 trials in 2,176 people found early intervention services better than usual care on all 13 outcomes measured, including fewer admissions, though effects on symptoms were small to moderate [8].

People who are severely unwell and at significant risk can be admitted to hospital under the Mental Health Act, with or without their agreement [4].

Living with psychosis

Recovery is common, and many people have one episode and no more.

• Protect sleep. Sleep loss is both a trigger and an early warning sign [2].
• Cannabis, especially daily use of high-potency types, is strongly associated with psychotic disorder, and services will advise cutting down or stopping [10].
• Ask your team for a written crisis plan and an advance statement.
• Attend the physical health checks. Some antipsychotic medicines affect weight, blood sugar and cholesterol [5].

You do not have to tell an employer your diagnosis. Any private therapist should be registered with the HCPC, BPS, BACP, UKCP or GMC.

When to speak to a professional

Book a GP appointment, and ask for a referral to Early Intervention in Psychosis, if you or someone you know:

• Is hearing, seeing or feeling things other people do not [1]
• Holds a belief others do not share that does not shift when questioned [1]
• Has become hard to follow in conversation, or jumps between unrelated subjects [1]
• Has withdrawn sharply, stopped sleeping, or stopped managing work, food or washing

Use the word psychosis and ask for an urgent referral. Getting into EIP quickly matters [6][9].

Get help the same day if the experiences are frightening, if the person cannot be kept safe at home, or if there are thoughts of self-harm or suicide. Ask the GP for an urgent appointment, call NHS 111 and choose the mental health option, or contact the crisis team.

Call 999 if anyone is in immediate danger, or is threatening to harm themselves or another person now.

If the person does not believe they are unwell. This is common, and part of the illness rather than stubbornness. Do not argue about whether the voices or beliefs are real. Say instead that you can see they are frightened or exhausted, and that you want them to see someone. You do not need their permission to get advice: GPs, NHS 111 and crisis teams take calls from relatives and carers. Write down what you have noticed, with dates.

Common questions

Is psychosis the same as schizophrenia?

No. Psychosis describes a set of experiences, and schizophrenia is one of several conditions in which they occur [2]. It also happens in bipolar disorder, severe depression, after childbirth, with drug use and in physical illness [2].

Are people with psychosis dangerous?

Violence is uncommon in people with psychosis, and they are more likely to be victims of violence than to be violent [4]. The greater risk is to the person themselves.

How long should you wait for treatment on the NHS?

The English access standard is treatment within two weeks of referral to an Early Intervention in Psychosis service, for ages 14 to 65 [6]. If the wait is longer, ask about that standard.

Clinical review pending

References

1. NHS. Psychosis: Symptoms. NHS. https://www.nhs.uk/mental-health/conditions/psychosis/symptoms/
2. NHS. Psychosis: Causes. NHS. https://www.nhs.uk/mental-health/conditions/psychosis/causes/
3. NHS. Psychosis: Diagnosis. NHS. https://www.nhs.uk/mental-health/conditions/psychosis/diagnosis/
4. NHS. Psychosis: Treatment. NHS. https://www.nhs.uk/mental-health/conditions/psychosis/treatment/
5. National Institute for Health and Care Excellence. Psychosis and schizophrenia in adults: prevention and management. NICE clinical guideline CG178, NCBI Bookshelf, 2014. https://www.ncbi.nlm.nih.gov/books/NBK555203/
6. NHS England. Implementing the early intervention in psychosis access and waiting time standard. NHS England, version 3, 2023. https://www.england.nhs.uk/wp-content/uploads/2023/03/B1954-implementing-the-early-intervention-in-psychosis-access-and-waiting-time-standard.pdf
7. NHS England Digital. Chapter 12: Psychotic Disorder. Adult Psychiatric Morbidity Survey: Survey of Mental Health and Wellbeing, England, 2023/24. https://digital.nhs.uk/data-and-information/publications/statistical/adult-psychiatric-morbidity-survey/survey-of-mental-health-and-wellbeing-england-2023-24/psychotic-disorder
8. Correll CU, et al. Comparison of Early Intervention Services vs Treatment as Usual for Early-Phase Psychosis: A Systematic Review, Meta-analysis, and Meta-regression. JAMA Psychiatry, 2018. https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2679768
9. Catalan A, et al. “Short” Versus “Long” Duration of Untreated Psychosis in People with First-Episode Psychosis: A Systematic Review and Meta-Analysis of Baseline Status and Follow-Up Outcomes. Schizophrenia Bulletin, 51(5), 2025. https://academic.oup.com/schizophreniabulletin/article/51/5/1206/7907905
10. Di Forti M, et al. The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study. The Lancet Psychiatry, 2019. https://www.thelancet.com/article/S2215-0366(19)30048-3/fulltext