Psychosis Algorithm

Safety

Red Flags — Exclude Organic Causes and Immediate Danger

Done

Screen for immediate risk and for organic causes before assuming a primary psychiatric illness. Keep yourself safe: sit near the door, have a colleague aware, and leave if the situation escalates.

Command hallucinations to harm Voices instructing violence to self or others — assess intent and ability to resist; commands alone do not automatically require 999. Use 999 for imminent risk, severe agitation, inability to maintain safety, serious physical illness or inability to assess safely; otherwise the crisis resolution and home treatment team or duty psychiatrist the same day

Suicidal intent with a plan Especially with persecutory beliefs, severe distress, recent loss or substance use → do not leave alone; crisis team same day or 999

Risk to others Specific threats, a named person in the delusional system, access to weapons → crisis team and police as needed; consider children in the household (safeguarding)

Full risk assessment Suicidal thoughts, intent, plan and means; intent to harm others; command hallucinations and ability to resist; specific threats, named victims, weapon access; vulnerability to exploitation or abuse; self-neglect, nutrition, hydration, accommodation; dependants and safeguarding; intoxication, withdrawal, impulsivity; capacity. Risk is dynamic — reassess when new information comes from relatives, carers, police or other professionals

Fever, headache or confusion Encephalitis (viral or autoimmune) or meningitis — neck stiffness, photophobia, seizures, reduced consciousness → 999

Fluctuating consciousness / disorientation Fluctuating attention, disorientation, impaired consciousness or abnormal arousal strongly suggest delirium or another organic cause → same-day hospital medical assessment to find the cause (confusion and delirium algorithm); 999 if reduced consciousness, seizures, fever or medically unstable. A normal brief cognitive screen does not exclude an organic cause

New seizures or focal signs Weakness, dysphasia, diplopia, abnormal movements → 999 or same-day ED (stroke, lesion, autoimmune encephalitis)

Severe self-neglect Not eating or drinking, unsafe living conditions, catatonic features (mutism, posturing, refusal to eat) → same-day assessment; 999/ED if catatonia with refusal of food/fluids or medical instability, or suspected NMS or serotonin syndrome

Intoxication or overdose A deliberate overdose or severe intoxication (stimulants, synthetic cannabinoids, hallucinogens) → 999 / immediate ED; toxicology in hospital. Milder intoxication → same-day ED

Puerperal onset New psychosis, mania, severe confusion or rapidly changing mental state during pregnancy or the postnatal year — especially the first weeks after birth — is a psychiatric emergency → immediate specialist perinatal mental-health assessment, usually within 4 hours of referral, with consideration of admission (NICE CG192). Do not leave the person alone; assess risk to mother and baby

NG12 Progressive neurological loss Late-onset psychosis with progressive, sub-acute loss of central neurological function (cognitive or personality change with focal features) → consider urgent direct-access MRI brain (NICE NG12 (updated April 2026), rec 1.9.1)

Risk to self and others is the first judgement because it decides where the rest of the assessment happens. A minority of apparent first-episode psychoses have a medical cause — autoimmune encephalitis, CNS infection, metabolic disturbance, a brain lesion or substance intoxication — and features such as fluctuating consciousness, disorientation, seizures, focal signs or fever should make you think organic first. Postpartum psychosis can escalate within hours and carries suicide risk and risk to the baby, so it needs immediate specialist perinatal assessment, ideally within 4 hours. Command hallucinations are not an automatic predictor of action, but combined with intent, distress or previous violence they signal high risk that should never be managed alone in primary care.

Diagnose

Confirm Psychotic Features — Core Symptom Screen

Done

Identify positive, negative and disorganised symptoms, the time course, and the effect on function. Ask open questions first ("Has anything strange or puzzling been happening?") before specific ones.

Positive symptoms

Hallucinations (usually auditory — commenting, arguing or commanding voices); delusions (persecutory, reference, grandiose, control); thought insertion, withdrawal or broadcasting; passivity experiences

Negative symptoms

Blunted affect, poverty of speech, loss of motivation, anhedonia, social withdrawal — often precede florid symptoms by months (prodrome) and are easily mistaken for depression

Disorganisation

Formal thought disorder (loosening of associations, tangential speech), odd or disorganised behaviour, incongruous affect

Describe, don't classify

Do not wait for diagnostic duration criteria before referral. Describe the presentation as first presentation of psychosis, acute psychosis, psychosis with mood symptoms, substance-related or medically suspected psychosis, or attenuated/transient psychotic symptoms. Formal classification is undertaken by the specialist mental-health service

Collateral history

Family or friends, with consent where possible: previous baseline, when the change began, drugs and alcohol, sleep, stressors, any threats or unusual behaviour

Mental state exam

Appearance, behaviour, speech, mood, thought form and content, perception, cognition (orientation, attention), insight, and risk to self, others and from others

Attenuated symptoms

Brief or low-intensity psychotic experiences with distress or decline in function may indicate increased risk of psychosis → refer without delay for specialist assessment (NICE CG178, 2014)

Accurate description of symptoms and time course determines urgency and route, but the diagnostic label is for the specialist team. Brief psychotic episodes can resolve, yet they still need urgent assessment because they can be the start of a longer illness. Negative symptoms and the prodrome (social withdrawal, falling performance at work or college) are frequently missed and often drive long-term disability. When insight is impaired, the collateral account is usually the most reliable source, and it also reveals risk information the patient may not share. Recording the patient's own words for delusions and voices helps the receiving team and allows change to be tracked.

Diagnose

Differential Diagnosis — Classification

Done

Separate primary psychotic disorders from affective, substance-related and organic causes. More than one can coexist.

Primary psychosis

Schizophrenia, schizoaffective disorder, delusional disorder, acute and transient psychosis → Early Intervention in Psychosis if first episode (formal classification by the specialist team)

Mania with psychosis

Elevated or irritable mood, grandiosity, reduced need for sleep, pressured speech, overactivity; delusions usually grandiose → urgent psychiatric assessment (NICE CG185, bipolar disorder, 2014)

Psychotic depression

Severe low mood with mood-congruent delusions (guilt, poverty, illness, nihilism) or derogatory voices; high suicide risk → urgent psychiatric assessment

Substance-induced

Cannabis (especially high-potency), synthetic cannabinoids, stimulants, hallucinogens, ketamine; alcohol withdrawal hallucinosis. Symptoms closely tied to use; may persist beyond intoxication

Medication-induced

Corticosteroids, levodopa and dopamine agonists, anticholinergics, mefloquine, some antiepileptics, isotretinoin (mood and behaviour change)

Organic / secondary

Delirium, autoimmune encephalitis (especially anti-NMDA receptor), epilepsy (particularly temporal lobe), thyroid disease, hypoglycaemia and metabolic disturbance, steroid or dopaminergic medication, intoxication or withdrawal, dementia (especially Lewy body), HIV/syphilis where clinically indicated, Wilson's disease (younger person with movement, psychiatric or hepatic features), intracranial lesion or stroke, head injury, B12 deficiency, Huntington's disease

Not psychosis

Culturally shared beliefs, overvalued ideas, obsessional thoughts recognised as one's own, PTSD re-experiencing, dissociative experiences, autism-related differences in communication

Treatment diverges by cause: bipolar disorder needs mood stabilisation and has its own guideline (CG185), psychotic depression needs combined treatment and careful suicide-risk management, and organic psychosis needs the medical cause treated. Substance-induced symptoms are common and often overlap with a primary disorder, so a positive drug history does not end the assessment. Early Intervention in Psychosis services should be accessible to anyone with a first episode or first presentation of psychosis, irrespective of age or the duration of untreated psychosis (NICE CG178), so uncertainty about the category is a reason to refer, not to wait. Late-onset psychosis (over about 60) should prompt a particularly careful search for delirium, dementia, sensory loss and medication effects.

Diagnose

Targeted Examination — Physical Causes

Done

A physical examination is part of every new presentation of psychosis and gives the baseline needed before antipsychotic treatment.

Observations

Temperature, pulse, BP, RR, SpO₂, capillary glucose — fever or tachycardia with psychosis suggests an organic cause, intoxication or withdrawal

Neurological

Cranial nerves, focal deficits, gait, cerebellar signs, abnormal movements, meningism — any new abnormality → same-day neurology or ED

Cognition

Orientation and attention (4AT if any suspicion of delirium: ≥4 = possible delirium). Disorientation points away from primary psychosis, but normal orientation does not exclude organic disease — some people with encephalitis, mania or psychosis are initially orientated

Eyes

Pupil size (stimulants dilate, opioids constrict), nystagmus (intoxication, Wernicke's), Kayser-Fleischer rings (rare — Wilson's disease)

Thyroid

Goitre, tremor, tachycardia, eye signs — thyrotoxicosis can mimic mania or agitation

Substance signs

Injection marks, nasal damage, smell of alcohol, withdrawal tremor and sweating

Baseline for treatment

Weight (plotted), waist circumference, pulse, BP, and any existing movement disorder — CG178 lists these as baseline measures before an antipsychotic

People with severe mental illness have far more physical illness and die considerably earlier than the general population, mostly from cardiovascular and respiratory disease, and much of this is preventable. A first examination establishes the baseline for antipsychotic monitoring and excludes treatable medical causes. NICE CG178 lists weight, waist circumference, pulse and blood pressure, glucose or HbA1c, lipids, prolactin, movement disorders and diet and activity as baseline measures before an antipsychotic is started. A neurological examination matters because encephalitis, CNS tumours and neurodegenerative disease can all present with psychiatric symptoms before obvious neurological signs.

Diagnose

Investigations — Exclude Organic Cause and Set a Baseline

Done

Send what you can at the first contact, but do not let tests delay an urgent referral.

Bloods — first-line

FBC U&E LFT TFT Calcium B12 / folate (where relevant) HbA1c or fasting glucose Lipids Prolactin (the last three are CG178 antipsychotic baseline tests). CRP only if infection, inflammatory disease or systemic illness is suspected

Infection screen

HIV and syphilis serology where there are risk factors, atypical features or relevant clinical context — universal serology is not required for every new presentation. Autoimmune antibodies (for example anti-NMDA receptor) are a specialist test — not requested routinely in primary care — considered with rapid onset, seizures, dyskinesias or abnormal movements, catatonia, autonomic instability, fluctuating or reduced consciousness, prominent cognitive decline or speech disturbance

Urine drug screen

Ask non-judgementally about alcohol, cannabis, stimulants, novel psychoactive substances and prescribed medication. Consider testing with consent where the result will influence management, diagnosis or safety planning — not as routine screening (NICE CG120). A positive result does not exclude a primary psychosis; a negative one does not exclude synthetic cannabinoids or substances taken outside the detection window

Pregnancy test

Assess pregnancy status in anyone who could be pregnant before prescribing, but do not delay emergency psychiatric treatment. Antipsychotics in pregnancy need specialist perinatal involvement and an individual risk–benefit discussion (NICE CG192)

ECG

Before an antipsychotic if the SPC specifies it, if examination shows cardiovascular risk, or there is a personal history of cardiovascular disease (NICE CG178). A prolonged QTc → discuss with the prescribing psychiatrist

Neuroimaging

Not routine in initial first-episode assessment (NICE CG178). Consider MRI/CT for focal signs, seizures, progressive cognitive/personality change, delirium or reduced consciousness, significant head injury, atypical or late-onset presentation, suspected intracranial lesion or rapid neurological deterioration — via the specialist team, or NG12 urgent direct-access MRI (CT if MRI contraindicated) for progressive sub-acute neurological loss

Blood tests exclude common metabolic, endocrine and nutritional causes and form the physical-health baseline that the specialist team needs; sending them from primary care saves time. Prolactin, glucose and lipids are part of the CG178 baseline because antipsychotics differ widely in their effects on each. A drug screen informs the discussion about substance use but does not settle the diagnosis, since substance use and primary psychosis often coexist. The ECG criteria come from CG178: it is not mandatory for everyone, but many antipsychotics prolong the QT interval, and electrolyte disturbance or other QT-prolonging medicines add to the risk.

Refer

Referral Pathway — EIP and Urgent Psychiatry

Done

Almost every first presentation of psychosis needs specialist referral. The GP's role is recognition, risk assessment, an organic screen and a fast, well-informed referral.

999 / Emergency

Imminent risk of suicide or serious violence; reduced consciousness or delirium with medical instability, seizures or suspected encephalitis; severe intoxication or overdose; severe agitation where safe assessment is impossible; NMS or serotonin syndrome; postpartum psychosis with immediate risk or inability to care safely for mother/infant; catatonia with refusal of food/fluids or medical instability

Same-day

First episode with significant risk, severe distress, severe self-neglect or poor engagement; mania with psychosis; severe psychotic depression; acute deterioration in established illness; psychosis with significant substance misuse → crisis resolution and home treatment team or duty psychiatrist (NICE CG178). Suspected organic psychosis or delirium without immediate life-threatening features → same-day hospital medical assessment. Postpartum onset → immediate perinatal mental-health assessment (within 4 hours)

EIP — urgent

All first-episode or first-presentation psychosis, any age, regardless of duration (NICE CG178, 2014). Treatment should start in EIP within 2 weeks of referral (NICE QS80, 2015; NHS England access and waiting time standard, 2016). Refer directly to the local EIP team where possible; confirm the referral is received and follow up if contact does not occur. The 2-week standard is an EIP access standard — it does not replace same-day crisis or emergency assessment

Specialist assessment

Attenuated or transient psychotic symptoms with distress or decline → refer without delay to a specialist mental health or EIP service (NICE CG178)

Children and young people

Under 14: CAMHS. Aged 14–17: CAMHS or EIP depending on local arrangements and presentation. Sustained psychotic symptoms for 4 weeks or more → urgent specialist referral; attenuated or transient symptoms with distress, impairment or help-seeking → refer without delay; crisis referrals seen within 4 hours. Do not start an antipsychotic in primary care without consulting a child and adolescent psychiatrist (NICE CG155, 2013, updated 2016)

Mental Health Act 1983

If the person refuses assessment and is at risk: request an MHA assessment via the Approved Mental Health Professional (AMHP) service — an application needs two doctors, one section 12 approved, ideally one who knows the patient. Police can use section 136 anywhere except a private dwelling; section 135 needs a warrant to enter premises

Referral content

Symptoms in the patient's words, duration, risk assessment, substance use, physical findings, blood results, medication, safeguarding and carer details

A shorter duration of untreated psychosis is associated with better outcomes, which is why QS80 sets a 2-week standard for starting treatment in EIP and why GPs should refer on suspicion rather than waiting for diagnostic certainty. EIP services provide a full package of medication, psychological therapy, family work, vocational and educational support. CG178 asks that people presenting to EIP are assessed without delay and that those in crisis are referred to crisis resolution and home treatment teams. Knowing the Mental Health Act roles (AMHP, section 12 doctor, and the limits of police powers under sections 135 and 136) lets the GP act quickly and lawfully when a person at risk declines help — a common SCA scenario.

Treat

Pharmacological Management — Antipsychotic Initiation

Done

GP role: do not start an antipsychotic for a first presentation of sustained psychotic symptoms in primary care unless it is done in consultation with a consultant psychiatrist (NICE CG178). Treatment is normally started and supervised by EIP or the CMHT; the GP continues it under shared care.

Choosing an antipsychotic

Shared decision specialist-led

CG178 names no single first-line drug: the choice is made with the person (and carer if they agree), weighing metabolic effects (weight gain, diabetes), extrapyramidal effects (including akathisia), cardiovascular effects (QT), hormonal effects (prolactin) and other unpleasant effects. Doses per BNF, starting low.

Trial and response

Optimum dose for 4–6 weeks

Carry out a trial at optimum dosage for 4–6 weeks, recording indications, expected benefits, side effects and adherence (NICE CG178). Avoid combining regular antipsychotics except briefly when switching.

Acute agitation (bridge)

Oral benzodiazepine advice only

Only on the advice of the crisis team or psychiatrist, short term, dose per NICE/SPC. Avoid in respiratory compromise and intoxication with other sedatives. Do not prescribe or administer rapid tranquillisation in routine general practice — urgent sedation is delivered by the crisis/acute mental-health team or ED under the local protocol with airway, respiratory and cardiovascular monitoring.

Treatment-resistant

Clozapine specialist only

Offered when illness has not responded to adequate doses of at least 2 different antipsychotics, at least one a non-clozapine second-generation drug (NICE CG178). Initiated and monitored by specialist services only; requires registration with the relevant brand monitoring service (CPMS, DMS or ZTAS), which uses WBC and neutrophil results (green/amber/red; do not apply EMA/US ANC-only thresholds unless specifically agreed with the monitoring service and specialist team) — FBC typically weekly for 18 weeks, 2-weekly to 1 year, then 4-weekly (per monitoring service and product requirements). Record it on the GP system. Stopping or markedly reducing smoking, pneumonia or serious infection, and interacting medicines can raise clozapine levels substantially — contact the clozapine team before any dose change. Always ask about constipation: clozapine-related gastrointestinal hypomotility can be life-threatening and needs prompt treatment.

Pregnancy and breastfeeding

Perinatal specialist advice specialist

Individual risk–benefit discussion with perinatal mental health (NICE CG192); pregnancy does not automatically mean switching medication. Do not stop effective antipsychotic treatment abruptly — relapse may endanger patient and baby. Monitor for gestational diabetes and excessive weight gain. Prolactin-raising drugs may affect fertility. Depots generally avoided in pregnancy unless stable on one with significant history of non-adherence. Clozapine, lithium and some antipsychotics need specialist advice in breastfeeding.

BaselineWeight and BMI, waist, pulse, BP, HbA1c or fasting glucose, lipids, prolactin, movement disorders, nutritional status, diet and activity; ECG if required by the SPC, cardiovascular risk, personal history of cardiovascular disease or inpatient (NICE CG178)

Weeks 1–6Weight weekly; watch for akathisia, dystonia, parkinsonism, sedation; ask about adherence

12 weeksWeight, pulse, BP, glucose or HbA1c, lipids; movement disorders (NICE CG178)

1 year, then annuallyWeight, waist circumference, pulse, BP, glucose or HbA1c, lipids; prolactin if symptomatic or on a prolactin-raising drug per local protocol; movement disorders at review. Secondary care monitors for at least 12 months or until stable, then transfers under agreed shared care (NICE CG178)

Next steps: see Psychosis and schizophrenia

Antipsychotics differ more in side effects than in efficacy, which is why CG178 frames the choice as a shared decision rather than naming a preferred drug. Some cause marked weight gain and diabetes risk; others cause more akathisia, prolactin rise or QT prolongation. Starting low reduces extrapyramidal effects, and akathisia is easily mistaken for worsening agitation. A 4–6 week trial at an adequate dose is needed before judging response. Clozapine is the evidence-based option for treatment-resistant schizophrenia; neutropenia monitoring is mandatory and GPs must know the patient is taking it, because constipation, infection and changes in smoking (which alter clozapine levels) can be dangerous.

Lifestyle

Non-Pharmacological Support — Recovery and Wellbeing

Done

NICE CG178 recommends offering psychological interventions — CBT for psychosis and family intervention — alongside medication for a first episode.

CBT for psychosis One-to-one, at least 16 planned sessions, following a treatment manual (NICE CG178). Accessed via EIP or CMHT psychology

Family intervention At least 10 planned sessions over 3 months to 1 year, with or without other families (NICE CG178; NICE QS80 statement 3)

Cannabis High-potency and frequent cannabis use can precipitate, worsen or prolong psychosis. Advise cessation/reduction and refer to an integrated substance-misuse pathway where needed — do not exclude people from mental-health services because of substance use (NICE CG120)

Physical health Stop-smoking support (smoking changes alter clozapine and olanzapine levels), physical activity, diet advice and weight management, vaccination and cardiovascular-risk management — antipsychotics add to cardiovascular risk. Ask about sexual dysfunction and prolactin symptoms, dental health, constipation, sleep apnoea risk with weight gain and sedation, interactions and adherence

Carer support Carer's assessment, information about the illness and the care plan, and signposting to Rethink Mental Illness, Mind and local carers' groups

Work and education Supported employment (Individual Placement and Support) via EIP helps people return to work or study

Alcohol and other drugs Non-judgemental approach; dual-diagnosis pathway if substance use is significant

Sleep and routine Regular sleep and daily structure; disrupted sleep is a common early sign of relapse

Safeguarding and housing Consider dependants, vulnerability to exploitation and housing instability; involve social care and raise safeguarding concerns where needed

CG178 places CBT for psychosis and family intervention alongside antipsychotic medication, and QS80 makes family intervention a quality statement. Family intervention helps families understand the illness, reduce conflict and recognise early warning signs. High-potency and frequent cannabis use can precipitate, worsen or prolong psychosis (Di Forti et al., 2019), and continued use after a first episode is linked with relapse. Smoking is common among people with psychosis and is a major contributor to their excess cardiovascular and respiratory death; offering cessation support is one of the most effective things primary care can do.

Safety

Follow-Up, Monitoring and Safety-Netting

Done

The GP keeps a shared-care role with EIP or the CMHT; physical health monitoring is a core primary-care responsibility.

Within days

Confirm EIP or crisis team contact has happened; if not, chase. Reassess risk at each contact

1–2 weeks

Tolerance of medication, akathisia (inner restlessness, pacing — often mistaken for worsening psychosis), dystonia, sedation, adherence

12 weeks

Weight, pulse, BP, glucose or HbA1c, lipids, movement disorders; mood and suicide risk (post-psychotic depression is common). Clozapine: ask about constipation and smoking changes

Annual

Physical health check at least once a year (NICE CG178): weight/BMI, waist, BP, pulse, glucose or HbA1c, lipids, smoking, alcohol and drugs, CVD risk; also dental, cervical and other screening, and medication review

Relapse plan

Record personal early warning signs with the patient and carer (sleep change, withdrawal, suspiciousness, stopping medication) and who to contact

999 safety-net

Voices telling them to harm themselves or others and they feel they may act, intent to harm, severe agitation, high fever with rigidity or confusion (possible neuroleptic malignant syndrome)

Same-day

Clear deterioration in mental state, carer concerns, stopped medication, acute dystonia, marked restlessness, or no contact yet from the specialist team

Wording

"If things get worse, or you feel you might act on the voices, call 999 or go to A&E. You can call NHS 111 and choose the mental health option at any time, and here is the crisis team's number. I will check on Friday that the early intervention team has been in touch."

Referrals get lost, and people with new psychosis often do not chase them, so a GP check within days closes the loop. Metabolic changes appear early on some antipsychotics, which is why CG178 builds in weekly weights and a 12-week check. Neuroleptic malignant syndrome is rare but life-threatening: fever, rigidity, altered consciousness and autonomic instability after starting or increasing an antipsychotic need emergency admission. Written relapse plans allow earlier intervention and fewer admissions. For the SCA, examiners look for a risk assessment that covers self, others and vulnerability, involvement of family with consent, specific safety-netting routes and a named follow-up.