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Psychotic Disorders (Psychosis)

NICE clinical guideline [CG178] Psychosis and schizophrenia in adults: prevention and management. Last updated: Mar 2014. Last reviewed: Jul 2025.

Psychotic Disorders (Psychosis)

Psychotic Disorders Overview

Primary Psychotic Disorders

[Ref]

Disorder High-yield distinguishing features
Schizophrenia
  • At least 2 of the following active-phase symptoms:
    • Delusions
    • Hallucinations
    • Disorganised speech
    • Grossly disorganised or catatonic behaviour
    • Negative symptoms (i.e. diminished emotional expression, or avolition)
  • Duration: ≥6 months, including ≥1 month of active symptoms
  • Associated with marked functional impairment
Schizophreniform disorder
  • Same schizophrenia active-phase symptoms criteria
  • Duration: 1-6 months
  • Marked functional impairment is NOT required
Schizoaffective disorder
  • Schizophrenia active-phase symptoms PLUS a major depressive or manic episode
  • Mood episodes are present for the majority of the illness
  • ≥2 weeks of delusions or hallucinations without a major mood episode
Brief psychotic disorder
  • Sudden onset of psychosis (delusions, hallucinations, disorganised speech and/or grossly disorganised or catatonic behaviour)
  • Duration: 1 day – 1 month
  • Followed by a full return to previous level of functioning
Delusional disorder
  • ≥1 Delusion
  • Duration: ≥1 month
  • No prominent additional psychotic features (specifically, the schizophrenia active-phase symptoms criteria is NOT met)

Secondary Psychosis and Other Mimics

Important mimics / differentials: [Ref1][Ref2]

Disorder High-yield distinguishing features
Substance / medication-induced psychotic disorder (drug-induced psychosis)
  • Presence of delusion and/or hallucination
  • Clear temporal relationship: symptoms develop during or within 1 month of substance intoxication or withdrawal
  • Common substances
    • Cannabis
    • Stimulants (esp. cocaine and amphetamines)
    • Hallucinogens (e.g. LSD)
    • Alcohol withdrawal
  • Common medications
    • Mainly levodopa and dopamine agonists
    • Systemic corticosteroids
Psychotic disorder due to another medical condition (secondary / organic psychosis) New psychosis (esp. prominent visual hallucinations) + neurological / systemic abnormalities or atypical presentation → consider secondary / organic psychosis

Key causes:

  • Lewy body dementia
  • Brain tumour or other structural brain lesions
  • Autoimmune encephalitis (esp. anti-NMDA receptor encephalitis)
  • Wilson disease
Mania with psychotic features (bipolar disorder)
  • Psychotic symptoms plus prominent manic syndrome (e.g. elevated / irritable mood, increased activity / energy, reduced need for sleep, pressured speech)
  • Psychosis occurs in the context of the mood episode (unlike schizoaffective disorder where psychosis also occurs independently of a major mood episode)
Schizotypal personality disorder
  • Longstanding pattern beginning by early adulthood
  • Eccentric idea / behaviour + magical thinking / ideas of reference + interpersonal difficulties
  • No obvious psychotic episodes
Schizoid personality disorder
  • Longstanding pattern beginning by early adulthood
  • Not interested in others, resulting in social isolation + no or few friends + not interested in relationships
  • No odd beliefs, perceptual distortions or psychosis

Psychosis Features

There are 4 core features of psychosis: [Ref]

Core feature Core concept
Delusions Abnormal beliefs that are firmly held despite evidence to the contrary
Hallucinations Abnormal perceptions occurring without a corresponding external stimulus
Disorganised thoughts or speech Abnormal thought / speech
Disorganised or abnormal behaviour Abnormal actions

Negative symptoms (e.g. lack of motivation, social withdrawal, reduced speech) may accompany psychotic disorders, particularly schizophrenia, but are covered in more detail in the schizophrenia article.

Negative symptoms are NOT defining features of psychosis.

1. Delusions

Common types of delusion:

Delusional theme Description Example vignette
Persecutory Persecutory delusions are the most common type of delusion [Ref]

Belief that another person, group or organisation intends to harm, threaten, monitor or conspire against him/her

A man believes MI5 is secretly monitoring him and has installed cameras in his home despite no evidence
Referential Belief that neutral events, comments or media have a special personal meaning directed specifically at him/her A woman believes a newsreader is sending coded messages specifically to her during television broadcasts
Grandiose Belief that him/her has exceptional power, ability, status, identity or importance A man believes he has been personally chosen by God to save the world
Erotomanic Belief that another person is in love with them, despite little or no evidence or relationship A woman believes a famous actor is secretly in love with her and communicates this through their social media posts
Somatic Belief concerning an abnormality or change in the body or health despite contrary medical evidence A man remains convinced that parasites are living underneath his skin despite repeated normal examinations
Nihilistic Belief that oneself, part of the body or the world no longer exists, is dead or has been destroyed A woman believes that she is already dead and her internal organs have stopped existing
Jealous Belief that a partner is being unfaithful despite inadequate evidence A man is convinced his wife is having an affair with a colleague despite there being no evidence

Thought alienation and passivity phenomena:

Phemonemon Description Example vignette
Thought insertion Belief that thoughts have been placed into the person’s mind by an external force and are not their own A man believes that the government is placing thoughts into his mind
Thought withdrawal Belief that an external force is removing thoughts from the person’s mind A woman believes that someone is taking thoughts out of her mind, causing her thoughts to suddenly disappear
Thought broadcasting Belief that the person’s thoughts are being transmitted or are accessible to other people A man believes that people on the bus can hear his thoughts even though he has not spoken
Passivity (delusions of control) Belief that one’s actions, impulses, emotions or bodily experiences are being controlled by an external force A woman believes that an outside force is controlling her arm movements and making her walk

Some named delusional syndromes:

Name Meaning
De Clérambault syndrome = Erotomanic delusion
Cotard syndrome = Nihilistic delusion
Capgras syndrome Belief that someone familiar has been replaced by an identical-looking impostor
Fregoli syndrome Belief that different people are actually the same person appearing in different disguises

2. Hallucinations

Definition: a perception-like experience that occurs without a corresponding external stimulus and is experienced as real rather than voluntarily imagined

Hallucination type Description Example vignette
Auditory Perception of sounds or voices without an external auditory stimulus A man repeatedly hears two voices discussing his behaviour despite nobody else being present
Specific patterns of auditory hallucinations:

  • Second-person voices – voice speaks directly to the patient (e.g. “you are worthless”)
  • Third-person voices – voice talks about the patient (e.g. 2 voices discussing what the patient is doing)
  • Running commentary – voice continuously comments on the patient’s actions (e.g. “He is getting dressed, now he is leaving the house)
  • Command hallucinations – voice instructs the patient to do something (e.g. to harm themselves)
Visual Perception of people, objects, shapes or scenes that are not actually present An older woman with cognitive decline repeatedly sees unfamiliar children and animals walking around her home despite nobody being there
Tactile False perception of touch or movement on the skin without an external stimulus A man using stimulants repeatedly feels insects crawling underneath his skin despite nothing being present
Somatic False perception of an internal bodily sensation or change without a corresponding physical cause A woman describes feeling that her internal organs are moving around inside her abdomen despite normal examination and investigations

Auditory hallucinations are more characteristic of primary psychotic disorders (e.g. schizophrenia) [Ref]

Prominent visual hallucinations should raise suspicion of a secondary / organic cause of psychosis [Ref]

Tactile hallucinations should particularly raise suspicion of a substance-related cause [Ref]

3. Disorganised Thoughts or Speech

Type Description Example vignette
Derailment (loose associations) Speech moves between ideas with weak or illogical connection A man is asked why he stopped working and says, “My manager was difficult. Managers wear suits. Suits are made in factories. Factories control the weather”
Tangentiality When asked a question, the person begins with a relevant response but moves progressively away from the question and never actually answers it A woman is asked, “Have you been sleeping well?” She talks about her noisy neighbours, then the council, then local taxes and roadworks, but never says how she has been sleeping
Circumstantiality When asked a question, the person gives excessive unnecessary detail and repeatedly digresses, but eventually returns to the point and answers the question A man is asked where he lives and describes when he moved there, his neighbours, the nearby supermarket and his bus route before eventually giving his address
Word salad (incoherence) Overall meaning of the speech cannot be understood, although individual words are recognisable A man says, “Blue window Tuesday runs the television because shoes are sleeping tomorrow”
Neologisms The person creates new words that have a particular meaning to them only A woman repeatedly says that the doctors are using a “braincaster”, explaining that this is a machine that sends thoughts directly into her head
Clang associations Words are chosen because they rhyme or sound similar, rather than because they are logically connected in meaning A man says, “The train brings rain to my brain, causing pain again on the plain”
Thought blocking The person’s chain of thought suddenly stops, often in the middle of a sentence, and they may be unable to recall what they were going to say A woman says, “I came to hospital because yesterday I was…”, suddenly becomes silent for several seconds, then says she cannot remember what she was thinking about

Most easily confused terms:

  • Circumstantiality → gives lots of unnecessary detail but eventually answers the question
  • Tangentiality → goes off-topic and never answers the question, although the sequence may still be understandable
  • Derailmentjumps between topics that are only weakly or illogically connected

4. Disorganised or Abnormal Behaviour

Category Specific examples
Grossly disorganised / bizarre behaviour
  • Bizarre outfit (e.g. wearing several heavy coats in summer because the person believes they protect against radiation)
  • Socially inappropriate behaviour
  • Purposeless agitation
  • Behaviour driven by delusional beliefs
Catatonic behaviour Marked abnormalities of movement and responsiveness:

  • Stupor – markedly reduced movement and responsiveness
  • Mutism – little or no verbal response
  • Posturing – spontaneously maintaining unusual or bizarre postures (e.g. holding the arms rigidly flexed for a prolonged period of time)
  • Negativism – resistance to instructions or attempts to move the patient
  • Echolalia – repeating another person’s speech
  • Echopraxia – imitating another person’s movement
Impaired goal-directed behaviour / self-care May present with

  • Poor hygiene
  • Not eating properly
  • Inappropriate clothing
  • Inability to manage basic ADLs

Psychosis Work Up

[Ref]

Category Assessment / investigation Rationale
Clinical assessment
  • Full medical history
  • Medication and substance-use history
  • Physical examination, including neurological examination
  • Identify secondary or organic causes of psychosis
  • Identify features suggesting an underlying neurological disorder
Blood tests
  • FBC
  • U&Es
  • LFTs
  • TFTs (thyroid dysfunction may cause psychiatric symptoms)
  • Calcium (hypercalcaemia may cause psychosis)
  • Vitmin B12 / folate
Urine studies Urine drug screen Consider when substance-induced psychosis is suspected
Neuroimaging CT / MRI brain Not routinely required in uncomplicated first-episode psychosis but consider if there are neurological signs, atypical features or suspicion of structural brain disease

Management

Management of first episode of psychosis:

  • Oral antipsychotic monotherapy, PLUS
  • Psychological interventions (both individual CBT and family intervention)

Choice of antipsychotic

  • NICE did NOT recommend a single preferred 1st line antipsychotic
  • Choice of antipsychotic should be guided by the side-effect profile and which side effect the patient is most willing to tolerate (including metabolic, extrapyramidal, cardiovascular and prolactin-related effects)
  • Clozapine is reserved for treatment-resistant schizophrenia and is not a routine 1st line antipsychotic (see below for indications)

Antipsychotic depots are long-acting injectables (usually IM injections) that can be considered if:

  • Patient prefers the method of administration, or
  • To avoid non-adherence

References

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