Acute Psychosis Management
Acute psychosis management involves rapid assessment, exclusion of organic causes, pharmacological treatment with antipsychotics, and psychosocial intervention.
Key Facts
Exclude organic causes first: Delirium, intoxication, autoimmune encephalitis, metabolic First-line: Oral atypical antipsychotic — risperidone 2mg, olanzapine 10mg, or aripiprazole 10mg IM antipsychotic (haloperidol 5mg + promethazine 25-50mg) if oral refused and patient is severely disturbed De-escalation should always be attempted before medication NICE CG178: All first-episode psychosis should be referred to EIP within 2 weeks Assess and manage risk: Self-harm, violence, self-neglect, vulnerability Consider MHA if patient refuses treatment and meets criteria for detention Monitor response and side effects from the outset — EPS, metabolic, QTc
Overview
Key Facts
Acute psychosis management requires a systematic approach prioritising safety, organic exclusion, pharmacological treatment, and engagement with specialist services.
Epidemiology
Acute psychosis presentations account for a significant proportion of psychiatric emergency referrals. First-episode psychosis has an incidence of ~32 per 100,000/year.
Aetiology
Causes of acute psychosis include primary psychiatric disorders (schizophrenia, bipolar mania, brief psychotic disorder), substance-induced psychosis (cannabis, amphetamines, cocaine), and organic causes (delirium, autoimmune encephalitis, metabolic).
Pathophysiology
- Dopaminergic excess in mesolimbic pathway → positive psychotic symptoms
- Antipsychotics block D2 receptors — onset of antipsychotic effect within days, but full response may take weeks
- Organic psychosis involves direct CNS pathology (inflammation, metabolic derangement, neurotoxicity)
Clinical Presentation
Acute Presentation
- Delusions, hallucinations (auditory most common), disorganised thinking/behaviour
- Agitation, fear, suspiciousness, aggression
- Reduced self-care, bizarre behaviour
- May present with catatonia
Assessment Priorities
- Safety: Immediate risk to self and others
- Organic screen: Exclude medical cause
- Mental state: Type and severity of psychotic symptoms
- Context: First episode vs relapse, substance use, medication compliance
- Capacity: Can patient consent to treatment?
Red Flags for Organic Psychosis
- Acute onset with confusion/fluctuating consciousness (delirium)
- Visual hallucinations predominant (delirium, LBD, substance)
- Fever, neck stiffness (meningitis/encephalitis)
- New-onset seizures (encephalitis, substance withdrawal)
- Young woman with movement disorder + psychosis (anti-NMDAR encephalitis)
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Drug-induced psychosis | Recent substance use, resolves with abstinence | Urine drug screen |
| Delirium | Fluctuating consciousness, medical cause | 4AT, septic screen, bloods |
| Bipolar mania | Elevated mood, grandiosity, episodic | Mood history, collateral |
| Anti-NMDAR encephalitis | Young woman, movement disorder, seizures | NMDA antibodies, MRI, EEG |
| Temporal lobe epilepsy | Brief episodes, automatisms | EEG |
| Psychotic depression | Mood-congruent delusions | PHQ-9, MSE |
Diagnosis / Investigation
Bedside
- Observations: NEWS2, glucose, temperature
- MSE: Comprehensive
- Urine drug screen: Cannabis, amphetamines, cocaine
- ECG: Baseline before antipsychotic
Bloods
- FBC, U&Es, LFTs, TFTs, CRP: Organic screen and baseline
- Calcium, glucose, B12: Metabolic causes
- HIV, syphilis: If clinically indicated
- NMDA receptor antibodies: If encephalitis suspected
Imaging
- MRI brain: Recommended for all first-episode psychosis
- CT head: If MRI unavailable or acutely indicated
Management
Non-pharmacological
- De-escalation: Calm environment, clear communication, offer choices
- 1:1 observation: If ongoing risk
- Referral to EIP: All FEP within 2 weeks (NICE CG178)
Pharmacological
Oral (if accepted):
- Risperidone 2mg OD, olanzapine 10mg OD, or aripiprazole 10mg OD
- Offer choice; explain side effects
- Low dose, titrate slowly
IM (if oral refused and severe disturbance):
- Haloperidol 5mg IM + promethazine 25-50mg IM
- OR lorazepam 1-2mg IM alone
- Post-RT monitoring: Pulse, BP, RR, SpO2 q15min for 1 hour
Benzodiazepines:
- Lorazepam 1-2mg for acute agitation, catatonia, or while awaiting antipsychotic effect
Referral Criteria
- All FEP — EIP team within 2 weeks
- Ongoing risk — crisis team or inpatient admission
- MHA assessment if refusing treatment and meets criteria
- Organic features — neurology/medicine
Prognosis
- Response to antipsychotic expected within 1-2 weeks (full response 4-6 weeks)
- First-episode psychosis: ~25% single episode, ~50% relapsing, ~25% chronic
- Early treatment (short DUP) improves long-term outcomes
- Adherence to medication significantly reduces relapse risk
Other Relevant Information
Acute Psychosis Management Algorithm
| Step | Action |
|---|---|
| 1 | Ensure safety — de-escalation |
| 2 | Exclude organic cause — observations, bloods, drug screen |
| 3 | Assess mental state and risk |
| 4 | Offer oral antipsychotic (low dose) |
| 5 | IM medication if oral refused and severe disturbance |
| 6 | Monitor and refer to EIP/crisis team |