Reasoning GP · Algorithm · 1-page summary
Psychosis — first episode and acute presentation
For: a first presentation of psychosis, or an acute presentation of psychotic symptoms, at any age, in primary care. Not for: long-term care of established schizophrenia (use the psychosis protocol). Under 18: block 6. Perinatal: block 1.
Core rule: judge risk and look for an organic cause first; then refer every first episode to Early Intervention in Psychosis (EIP) on suspicion — never wait for a diagnostic label or a full organic work-up.
0Stop — call 999 now — before the full history
- Imminent risk of suicide or serious violence, acting on voices commanding harm, agitation too severe to assess safely → 999
- Fever, headache or confusion (encephalitis, meningitis), reduced consciousness, new seizures or focal signs → 999 (focal signs: 999 or same-day ED)
- Deliberate overdose or severe intoxication; suspected NMS (fever, rigidity, confusion) or serotonin syndrome; catatonia refusing food/fluids or medically unstable; postpartum psychosis with immediate risk or unable to care safely for the baby → 999
- While waiting: do not leave them alone; sit near the door, colleague aware, leave if it escalates; consider children at home. Do not delay for bloods or a drug screen; no rapid tranquillisation in general practice.
1Triage — risk decides the route
| Finding | Action |
|---|---|
| Significant risk | Severe distress, self-neglect, poor engagement; mania or psychotic depression; relapse → Same-day crisis team / duty psychiatrist |
| Perinatal onset | Pregnancy or postnatal year → Immediate perinatal mental-health assessment, within 4 hours |
| First episode | No acute risk → Urgent EIP, any age, any duration; treatment starts within 2 weeks |
| Attenuated | With distress or decline → refer without delay (specialist mental health / EIP) |
2Screen — organic causes and risk
- Fluctuating attention, disorientation (delirium) or other suspected organic cause → Same-day hospital medical assessment; 999 if reduced consciousness, seizures, fever or unstable.
- Suicidal plan; threats, a named person, weapons → do not leave alone; crisis team Same-day or 999; police as needed; safeguard children.
- Severe self-neglect, catatonic features → Same-day assessment.
- Progressive sub-acute loss of central neurological function → consider Urgent direct-access MRI brain (NG12).
3Assess — send what you can; tests never delay referral
☐ Temp, pulse, BP, RR, SpO₂, capillary glucose ☐ Neuro exam, meningism; 4AT if delirium suspected (≥4 = possible delirium) ☐ Mental state; risk to self, others, from others; capacity ☐ Collateral, with consent ☐ FBC, U&E, LFT, TFT, calcium, HbA1c/glucose, lipids, prolactin; B12/folate where relevant ☐ Weight, waist ☐ Pregnancy status ☐ Drug screen, with consent, if it changes management ☐ ECG if SPC requires, CV risk or CVD history
Not routine: neuroimaging, universal HIV/syphilis serology, autoimmune antibodies.
4Classify — describe, don't label; causes coexist
- Primary psychosis — voices, delusions, thought disorder, negative symptoms → EIP; the specialist classifies.
- Mania with psychosis (elevated mood, little sleep, grandiosity) or psychotic depression (nihilistic delusions, high suicide risk) → Same-day psychiatry.
- Substance or medicine — cannabis, stimulants, ketamine, alcohol withdrawal, steroids, levodopa: use does not end the assessment.
- Uncertain — a reason to refer, not to wait. Not psychosis: shared cultural beliefs, obsessions, PTSD, dissociation.
5Treat today
- No antipsychotic for a first presentation unless agreed with a consultant psychiatrist (under 18: child and adolescent psychiatrist).
- Agitation: oral benzodiazepine only on crisis team or psychiatrist advice, short term; not with respiratory compromise or other sedatives. Doses: NICE/SPC, BNF, local formulary.
- Refuses help, at risk: Mental Health Act assessment via the AMHP service; police s136 not in a private dwelling; s135 needs a warrant.
- Cannabis, stimulants: advise stopping. Pregnant: never stop an effective antipsychotic abruptly; perinatal advice.
6Refer and follow up
- Letter: patient's words, duration, risk, substances, examination, bloods, medicines, safeguarding, carer. Confirm receipt; chase within days.
- Under 18: under 14 CAMHS; 14–17 CAMHS or EIP. Sustained ≥4 weeks → urgent; crisis seen within 4 hours.
- Via EIP/CMHT: CBT for psychosis, family intervention, carer's assessment.
- On antipsychotics: weight weekly for 6 weeks; at 12 weeks and yearly weight, pulse, BP, glucose/HbA1c, lipids. Clozapine: record it; ask about constipation and smoking changes.
7Never reassure by
- Normal orientation or brief cognitive screen (organic causes).
- Drug use or a positive screen; a negative screen (synthetic cannabinoids).
- A calm consultation — risk is dynamic; get collateral.
- The 2-week EIP standard when risk is significant.
- Waiting for duration criteria or a full organic work-up before referral.
- "Depression" when withdrawal and decline may be a prodrome.
8Safety-net — say it to patient and carer, then document it
999 “If things get worse, or you feel you might act on the voices, call 999 or go to A&E — also for intent to harm, severe agitation, or high fever with stiffness or confusion.” Same day: “Contact us or the crisis team today for clear worsening, carer concern, stopped medication, muscle spasms, marked restlessness, or no contact yet from the team. You can call NHS 111 and choose the mental health option at any time.”
Follow-up: give the crisis team's number; check within days that EIP has made contact; record early warning signs and who to contact in a relapse plan.
✓Safe to leave primary care only if — all five, documented
No block 0 trigger; risk to self, others and from others assessed
Observations, neuro exam and cognition done; no delirium; bloods sent
Route chosen (EIP, crisis, perinatal, CAMHS) and referral sent
Carer involved with consent; dependants and safeguarding considered
Safety-net and crisis number given; check-in within days booked
Summary of the full Reasoning GP psychosis algorithm, which holds the history, examination, investigations, treatment and monitoring detail and evidence. Sources: NICE CG178, QS80, CG155, CG185, CG192, CG120, NG12 (updated April 2026); NHS England EIP access standard; Mental Health Act 1983. Clinical reference — follow local crisis, Mental Health Act, safeguarding and referral policies and check doses: NICE/SPC, BNF.