Acute Psychosis

Acute psychosis requires organic causes to be excluded first before attributing symptoms to a functional psychiatric illness. In the acute setting, de-escalation is first-line; rapid tranquillisation (RT) is reserved for risk of harm to self or…

NICE NG10 Psychosis and Schizophrenia / MHA 1983 Framework

The pathway

1 · Exclude organic causes (priority)

Investigations: U&E, glucose, LFTs, TFTs, CRP, FBC, B12, folate, urine drug screen
CT/MRI head: if first episode psychosis, focal neurology, raised ICP, or age >40 at first episode
LP: if encephalitis suspected (viral encephalitis, anti-NMDAR encephalitis) — send CSF MC&S, HSV PCR, autoimmune encephalitis panel
ECG: before antipsychotics (QTc baseline)
Common organic differentials: encephalitis, hypoglycaemia, hyponatraemia, thyroid storm, uraemia, intoxication/withdrawal

2 · De-escalation (first-line)

MHPOD principles: low stimulation environment, calm non-confrontational approach, offer choice, use patient's name
Involve known staff or family if calming
Do not leave patient alone if high risk
Set clear, consistent limits
Document de-escalation attempts before RT

3 · Rapid tranquillisation (RT) — if risk of harm

Option 1 (oral): Lorazepam 1–2mg PO ± Haloperidol 5mg PO
Option 2 (IM): Lorazepam 1–2mg IM OR Haloperidol 5mg IM (not both IM simultaneously)
Option 3 (IM): Olanzapine 10mg IM — DO NOT combine with IM lorazepam (risk of cardiorespiratory arrest)
If known or suspected QTc prolongation: avoid haloperidol — use lorazepam alone
Allow adequate time between doses before re-dosing

4 · Post-RT monitoring

Observations every 5–10 minutes for 1 hour after RT
Monitor: pulse, BP, RR, SpO₂, conscious level
Have resuscitation equipment and flumazenil (benzodiazepine reversal) immediately available
Target: settled and safe, NOT unconscious

5 · Mental Health Act 1983 assessment

Section 2 (assessment): up to 28 days. Criteria: mental disorder warranting assessment, necessary for health/safety of patient or protection of others
Section 3 (treatment): up to 6 months. Criteria: mental disorder warranting treatment, appropriate treatment available
Requires: 2 doctors (one Section 12 approved) + AMHP (Approved Mental Health Professional)
Section 136: police power — up to 24 hours in place of safety
Section 5(2): doctor's holding power — up to 72 hours for inpatient

6 · Safeguarding and collateral history

Contact GP and mental health services for previous history, regular medications, known diagnoses
Check for Advance Statements or Care Plans (CPA)
Safeguard vulnerable adults and dependent children
Next of kin notification (with patient consent where possible)

7 · Ongoing management

If organic cause excluded: NICE NG10 — offer antipsychotic and psychological support
First-episode psychosis: low-dose antipsychotic (e.g. aripiprazole or risperidone)
Refer to Early Intervention in Psychosis (EIP) team
Mental Health Liaison or psychiatric team to review within 24 hours

Drugs

Drug	Dose	Route	Notes
Lorazepam	1–2mg	PO or IM	First-line RT. Do NOT give IM with IM olanzapine — risk of cardiorespiratory arrest. Monitor airway and SpO₂.
Haloperidol	5mg	PO or IM	Avoid if QTc prolonged or unknown. Check ECG first. Not for dementia-related psychosis.
Olanzapine	10mg	IM	Alternative RT. NEVER combine IM olanzapine with IM lorazepam. Oral (10mg) preferred if accepted.
Promethazine	25–50mg	IM	Sedating antihistamine used as adjunct to RT. Can combine with IM haloperidol safely. Useful if benzodiazepines avoided.
Flumazenil	200 micrograms over 15 seconds, then 100 micrograms every 60 seconds (max 1mg)	IV	Benzodiazepine reversal if over-sedated post-RT. Short-acting — re-sedation can occur. Monitor for 1h.

When to escalate

SpO₂ <94% or RR <10 after rapid tranquillisation — airway emergency, call crash team,Suspected organic encephalitis (fever + altered consciousness + seizures) — LP urgently, neurology input,Failure of RT after 2–3 doses — senior psychiatric and anaesthetic review,Neuroleptic malignant syndrome (hyperthermia, rigidity, autonomic instability after antipsychotics) — stop antipsychotic, ITU referral,QTc >500ms on ECG before or after antipsychotic — withhold further doses, cardiology advice,Patient absconding from hospital with active risk to self or others — Section 136 / police involvement

Reference: NICE NG10 Psychosis and Schizophrenia 2014 (updated 2023) / Mental Health Act 1983 Code of Practice 2015

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