1. Definition and clinical relevance
Psychosis is a syndrome characterised by a break from reality, manifest as hallucinations, delusions, disorganised thinking, or grossly disturbed behaviour. Schizophrenia is the prototypical primary psychotic disorder, typically emerging in late adolescence or early adulthood, and carrying substantial long-term morbidity if untreated. For an Australian intern, first-episode psychosis (FEP) is time-critical: the longer psychosis goes untreated, the worse the functional outcome. Interns are frequently the first clinician to assess these patients in emergency departments, and must rapidly distinguish primary psychiatric illness from organic or substance-induced causes before initiating treatment or arranging admission.
2. Key values, thresholds, scoring systems
| Parameter | Threshold or target |
|---|---|
| Duration of untreated psychosis (DUP) | Shorter DUP correlates with better prognosis; treatment should begin promptly |
| Antipsychotic trial duration before declaring inadequate response | At least 6 weeks at therapeutic dose |
| Treatment-resistant schizophrenia (TRS) definition | Failure of two adequate antipsychotic trials from different classes |
| Clozapine starting dose | 12.5 mg orally once or twice daily, titrated by 25-50 mg increments over 2-3 weeks toward 300 mg daily; maximum 900 mg daily |
| Clozapine FBC monitoring | Weekly for the first 18 weeks, then monthly (agranulocytosis risk) |
| Haloperidol oral (acute psychosis, treatment-naive) | 0.5-3 mg twice daily; up to 15 mg twice daily maximum |
| Risperidone oral (starting) | 2 mg nightly (4 mg if severe), titrated to maximum 8 mg nightly |
| Chlorpromazine oral (starting) | 75 mg as a single nocturnal dose, titrated to 300 mg maximum |
| Depot test dose (e.g. fluphenazine decanoate) | 12.5 mg; haloperidol decanoate 25 mg test dose |
| Procyclidine for acute dystonia (IM) | 5-10 mg IM, repeatable after 20 minutes; maximum 20 mg per day |
| Lithium target serum level | 0.4-1.0 mmol/L measured 12 hours post-dose |
| First-episode psychosis: minimum treatment duration before cautious dose reduction | Patient well for more than 12 months |
| Schizophrenia: ongoing treatment duration | Often many years; indefinite in recurrent illness |
Features pointing toward organic or drug-induced psychosis rather than primary psychiatric illness:
Acute onset within the preceding month, altered alertness, disorientation (especially worsening at night), age over 50 at first presentation, concurrent medical illness, or use of CNS-active medications (steroids, opioids, efavirenz) or recreational substances all raise the probability of an organic aetiology.
3. Approach: presentation and differential
History red flags in FEP
A prodromal phase of social withdrawal, declining school or work performance, and odd beliefs often precedes florid psychosis by months. Key positive symptoms include auditory hallucinations (voices commenting or conversing), persecutory or grandiose delusions, thought insertion, broadcasting or withdrawal, and passivity phenomena. Negative symptoms include blunted affect, poverty of speech, avolition, and anhedonia. Disorganised speech and behaviour round out the clinical picture.
Always ask about: substance use (cannabis, amphetamines, cocaine, ketamine, synthetic cannabinoids), prescribed medications, recent head trauma, family psychiatric history, perinatal complications, and any prior psychiatric contact. Schizophrenia has a neurodevelopmental basis and is associated with perinatal adversity.
Examination
Assess orientation, alertness, and cognition. Fluctuating consciousness or clear disorientation points away from primary psychosis. Vital signs, neurological examination, and a full physical assessment are mandatory in every FEP to exclude organic causes.
Differential diagnosis (in order of danger)
- Organic delirium (sepsis, metabolic disturbance, CNS pathology, hypoxia)
- Substance-induced psychosis (amphetamines, cannabis, alcohol withdrawal, synthetic cannabinoids)
- Bipolar disorder with psychotic features (manic or mixed episode)
- Brief psychotic disorder or schizophreniform disorder
- Schizophrenia
- Major depressive disorder with psychotic features
- Post-traumatic brain injury psychosis
- Medical conditions (thyroid disease, porphyria, autoimmune encephalitis, CNS tumour)
In elderly patients, assume a new psychotic presentation is organic until proven otherwise.
4. Investigations
Bedside
BSL (hypoglycaemia), oxygen saturation, ECG (QTc prolongation before antipsychotics), urine drug screen, urinalysis (UTI as delirium trigger).
Bloods
| Test | Purpose |
|---|---|
| FBC | Infection, anaemia, baseline before clozapine |
| UEC, creatinine | Renal impairment, electrolyte disturbance |
| LFTs | Hepatic encephalopathy, baseline |
| TFTs | Thyroid-induced psychosis |
| Calcium, magnesium, phosphate | Metabolic causes |
| Fasting glucose and lipids | Metabolic syndrome baseline before atypical antipsychotics |
| Prolactin | Baseline (antipsychotics raise prolactin) |
| Serum B12 and folate | Deficiency-related neuropsychiatric presentations |
| Blood cultures | If febrile |
| Syphilis serology, HIV | If risk factors present |
Imaging and further workup
CT brain (non-contrast initially) if first-episode psychosis with any neurological signs, head trauma history, or age over 50. MRI brain and EEG if autoimmune encephalitis or seizure disorder is suspected. Lumbar puncture if encephalitis cannot be excluded clinically.
5. Management
Initial resuscitation and safety
Ensure a safe environment. If the patient poses an immediate danger to themselves or others, admission is required, either voluntarily or under mental health legislation. If the aetiology of disturbed behaviour remains unclear, admit for investigation. Treat any identified organic cause concurrently (antibiotics for infection, glucose for hypoglycaemia, and so on).
Sedation when required
For acute agitation prior to or during assessment, oral options include diazepam 5-10 mg or lorazepam 1 mg (sublingually if needed), or chlorpromazine 25 mg orally (halve the dose in elderly patients). Intramuscular options include lorazepam 1.5-2.5 mg, haloperidol 1-3 mg, or chlorpromazine 25 mg IM. Avoid sedation in patients with COPD, epilepsy, or known recent use of alcohol, barbiturates, or illicit CNS depressants.
Antipsychotic therapy
Second-generation (atypical) antipsychotics are the first-line choice for FEP. They act via combined serotonin 2A and dopamine D2 antagonism (e.g. olanzapine, risperidone, quetiapine) or as partial agonists at dopamine and serotonin receptors (e.g. aripiprazole). Their side-effect profile, while more favourable than first-generation agents for movement disorders, includes weight gain, hyperglycaemia, dyslipidaemia, sedation, and hyperprolactinaemia. Metabolic parameters must be monitored regularly.
Start treatment-naive patients at low doses and titrate according to clinical response. Benefit is usually apparent within two weeks, with continued improvement over three to six months.
For treatment-resistant schizophrenia (failure of two adequate trials), clozapine is the agent of choice: approximately two-thirds of TRS patients respond. Initiate at 12.5 mg once or twice daily, increasing in 25-50 mg increments over two to three weeks to a target of around 300 mg daily, with a ceiling of 900 mg daily. Monitor FBC weekly for the first 18 weeks due to agranulocytosis risk, then monthly thereafter. Check temperature, pulse, and blood pressure daily during the first week.
Managing movement disorder side effects
Acute dystonia (torticollis, oculogyric crisis, opisthotonus, tongue protrusion) can occur within hours of starting a first-generation antipsychotic. Treat with procyclidine 5-10 mg IM, repeatable after 20 minutes to a daily maximum of 20 mg. Drug-induced parkinsonism responds to oral procyclidine 2.5 mg three times daily, titrated gradually to a maximum of 30 mg daily in divided doses. Akathisia (severe motor restlessness) can be managed with a benzodiazepine or a beta-blocker. Switching from a first-generation to a second-generation agent is an alternative strategy for all movement disorders. Tardive dyskinesia is a risk with prolonged first-generation antipsychotic use.
Psychological and social interventions
Psychoeducation for the patient and family reduces relapse rates. Cognitive behavioural therapy adapted for psychosis, cognitive remediation, and family interventions all have evidence of benefit. Social skills training, peer support, case management, and occupational therapy address the broad functional impact of psychosis on daily living, relationships, and employment. A multidisciplinary team approach improves functional outcomes.
Family members should be counselled to reduce household stress and expressed hostility. Explain clearly that schizophrenia is a treatable illness requiring long-term medication. Covert administration of medication (concealed in food or drink) is ethically problematic and can damage the therapeutic relationship long-term.
Adherence and long-acting injectable (depot) formulations
Non-adherence is the leading cause of relapse. Explore reasons: poor insight, intolerable side effects, stigma. Switching antipsychotic class often improves tolerability. Depot (long-acting injectable) formulations are particularly useful when oral adherence is unreliable or relapses are frequent. Always administer a test dose before commencing a depot regimen.
Involuntary treatment
In Australia, each state and territory has its own Mental Health Act. The general principle is that involuntary admission and treatment can be authorised when a person has a mental illness, lacks capacity or insight to consent to treatment, and poses a risk to their own safety or the safety of others, and where less restrictive alternatives have been considered. Involuntary orders authorise treatment of the mental illness only: the patient retains the right to refuse consent for unrelated medical procedures. Senior psychiatric involvement and, where available, an Authorised Mental Health Practitioner (AMHP equivalent in each jurisdiction) are required. Document clinical reasoning carefully.
Disposition
Admit if: FEP with safety concerns, diagnostic uncertainty, organic cause requiring inpatient workup, or risk of harm. Outpatient Early Psychosis Intervention (EPI) programs are appropriate for stable patients with adequate social support and low immediate risk. Ensure a clear follow-up plan before any discharge.
6. Australian-specific considerations
Early Psychosis Intervention programs
Australia has a well-developed network of headspace and Early Psychosis Youth Services (EPYS) centres. Referral to these services for young people with FEP is standard practice and improves long-term outcomes. Familiarity with local referral pathways is essential for interns.
State-based Mental Health Acts
Involuntary treatment legislation differs across jurisdictions. Each state and territory has its own Act, its own terminology for orders, and its own review tribunal. The underlying principles (risk, capacity, least restrictive alternative) are consistent, but the specific order names, durations, and review processes vary. Always check local legislation and involve the treating psychiatrist and mental health team early.
The named statutes by jurisdiction are: Mental Health Act 2007 (NSW); Mental Health and Wellbeing Act 2022 (Vic); Mental Health Act 2016 (Qld); Mental Health Act 2014 (WA); Mental Health Act 2009 (SA); Mental Health Act 2013 (Tas); Mental Health Act 2015 (ACT); and the Mental Health and Related Services Act 1998 (NT).
Aboriginal and Torres Strait Islander peoples
Psychosis in Aboriginal and Torres Strait Islander patients requires culturally safe assessment. Spiritual beliefs and experiences that are culturally normative must not be pathologised as delusions or hallucinations without careful cultural consultation. Engage Aboriginal Liaison Officers and, where available, Aboriginal Mental Health Workers. Rates of involuntary treatment are disproportionately high in this population; this demands particular attention to least-restrictive care, community-based options, and family involvement in decision-making. Social determinants including housing instability, trauma, and geographic remoteness significantly affect presentation, engagement, and outcomes.
Rural and remote considerations
Telehealth psychiatry consultation is widely available and should be activated early when specialist review is not locally accessible. Retrieval to a tertiary centre may be required for FEP with diagnostic uncertainty or high risk. Rural interns should know their local mental health on-call pathway and the process for initiating an involuntary assessment order before specialist arrival.
PBS and medication access
Clozapine is PBS-listed but requires registration with a clozapine monitoring program and mandatory FBC surveillance. Atypical antipsychotics including risperidone, olanzapine, quetiapine, and aripiprazole are PBS-listed for schizophrenia and related psychotic disorders. Long-acting injectable formulations are also PBS-listed. Confirm current PBS criteria at the time of prescribing.
Clinical pearls
- Always exclude an organic cause before attributing new-onset psychosis to a primary psychiatric disorder: altered consciousness, disorientation, or age over 50 at first presentation should trigger a full medical workup.
- Second-generation antipsychotics are first-line for FEP; monitor metabolic parameters (weight, fasting glucose, lipids) at baseline and regularly throughout treatment.
- Acute dystonia after a first-generation antipsychotic is treated with procyclidine 5-10 mg IM, repeatable after 20 minutes to a daily maximum of 20 mg.
- Clozapine is reserved for treatment-resistant schizophrenia and requires mandatory weekly FBC monitoring for the first 18 weeks due to the risk of agranulocytosis.
- Involuntary mental health orders in Australia authorise treatment of the mental illness only: the patient may still refuse consent for other medical interventions.
- In Aboriginal and Torres Strait Islander patients, culturally normative spiritual experiences must be carefully distinguished from psychotic symptoms, and Aboriginal Liaison Officers should be involved in assessment wherever possible.
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