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Psychosis and schizophrenia, first-episode presentation, antipsychotics, involuntary treatment

AMC CAT LO AMC_SYS_13LO AMC_KU_03LO AMC_KU_04LO AMC_KU_05LO AMC_KU_12LO AMC_SK_13LO AMC_SK_16LO AMC_SK_17LO AMC_SK_18LO AMC_SK_19LO AMC_SK_20LO AMC_SK_22 1,530 words
Free preview. This study note covers 12 learning objectives (AMC_SYS_13, AMC_KU_03, AMC_KU_04, AMC_KU_05, AMC_KU_12, AMC_SK_13, AMC_SK_16, AMC_SK_17, AMC_SK_18, AMC_SK_19, AMC_SK_20, AMC_SK_22) from the AMC CAT curriculum. Inside PRIMEX you get exam-style MCQ practice on this topic, an OSCE simulator covering all five AMC Part 2 station types, Ask PRIMEX for Australian-context clinical questions, and a curriculum tracker mapped to every blueprint patient group.

1. Definition and clinical relevance

Schizophrenia is a chronic psychotic disorder characterised by disturbances in thought, perception and behaviour. First-episode psychosis most commonly presents in young people under 35 years with positive symptoms (delusions, hallucinations, thought disorder) and frequently lack of insight.

Neurodevelopmental origins:

Clinical course:

Suicide risk:

2. Key values, thresholds and decision rules

Most patients with schizophrenia respond to an antipsychotic; however, the majority will relapse within two years if they stop medication. Around 25% of patients do not respond adequately despite being adherent, and these patients should be switched to alternative therapy, ultimately including clozapine.

Parameter Value / rule
Typical age of onset Young person, usually under 35 years
Deliberate self-harm before first presentation 10 to 14%
Suicide rate at 1 year (first-episode) 2.9 to 11%
Relapse after stopping medication Majority relapse within 2 years
Inadequate response despite adherence ~25% (consider treatment resistance)
Clozapine agranulocytosis risk ~0.8% over a treatment lifetime

Antipsychotic drug considerations (grounded):

Drug Key side effects Monitoring Depot available
Amisulpride Hyperprolactinaemia eGFR monitoring required if renal function impaired (renal excretion); safe in post-ictal psychosis No
Aripiprazole Akathisia (less than first-generation agents) No specific requirements Yes
Clozapine Myocarditis, constipation, hypersalivation, agranulocytosis Mandatory frequent blood count and clinical monitoring -

Emergency sedation while awaiting admission (grounded doses):

Route Agent and dose
Oral (first line) Lorazepam 1 to 2 mg PO, or chlorpromazine 50 to 100 mg PO
Intramuscular (if refused, severe agitation) Lorazepam 1 to 2 mg IM, or chlorpromazine 50 mg IM

Reduce doses in elderly patients. Avoid chlorpromazine if the patient is epileptic, has been drinking alcohol, or has taken barbiturates.

3. Approach: presentation and differential

History

The initial approach frequently comes from a relative or friend rather than the patient. Ask specifically about thoughts and perceptions. Enquire about characteristic first-rank type symptoms:

Elicit any history of drug misuse. Take a social and developmental history using open-ended questions, noting birth history (association with perinatal morbidity) and early development. Ask about prodromal features: social isolation or withdrawal, deterioration in functioning at home, school, grooming and hygiene, lack of energy, hypersomnia, inappropriate or dulled affect.

Crucially, assess risk to self and others, given the high rate of self-harm and suicide in this population.

Examination

Assess behaviour and appearance. Look for evidence of:

Differential

4. Investigations

Bedside

Bloods

Investigations should be guided by the clinical picture, particularly to exclude organic mimics such as delirium. A reasonable organic screen includes FBE, U&E, glucose, calcium, liver function tests, cardiac enzymes, ESR, CRP, oxygen saturation and MSU where indicated.

Baseline bloods are also required to guide and monitor antipsychotic therapy:

Imaging

Not specifically grounded; investigation should be guided by the clinical picture to exclude organic causes.

5. Management

Step 1: Assess risk and decide on admission

Ask whether the patient is a risk to self or others. If psychotic illness is suspected and the patient is at risk, arrange admission.

Step 2: Manage acute agitation

The acute phase usually requires hospitalisation. If sedation is needed while awaiting admission, try oral medication first (lorazepam 1 to 2 mg PO or chlorpromazine 50 to 100 mg PO). If refused and agitation is severe, consider lorazepam 1 to 2 mg IM or chlorpromazine 50 mg IM. Reduce the dose in elderly patients and avoid chlorpromazine in epilepsy, recent alcohol use, or barbiturate use.

Step 3: Antipsychotic treatment of the psychosis

Drug treatment targets the psychosis. Options include:

Choice is individualised, balancing efficacy against the diverse side-effect profile (metabolic, endocrine and neurocognitive), which requires regular clinician review. Aripiprazole causes less akathisia than first-generation agents. Amisulpride is a reasonable choice in post-ictal psychosis but requires eGFR monitoring in renal impairment.

Managing extrapyramidal side effects:

Step 4: Depot / long-acting injectable antipsychotics

Long-acting intramuscular ("depot") preparations allow scheduled administration by community mental health teams, assuring adherence in patients with limited insight. Aripiprazole is available in a depot form.

Step 5: Treatment resistance and clozapine

Around 25% of adherent patients do not respond adequately and should be switched to alternative therapy, ultimately clozapine. Traditionally reserved for treatment-resistant illness, there is growing evidence that clozapine should be introduced earlier where it is safe to prescribe. Mortality in schizophrenia is lower in the clozapine group. However, all patients on clozapine require mandatory frequent blood count and clinical monitoring, given the risk of agranulocytosis (a rare, life-threatening complication affecting ~0.8% over a treatment lifetime), as well as vigilance for myocarditis, constipation and hypersalivation.

Step 6: Adjunctive treatments

ECT may be considered for schizophrenia in combination with antipsychotic medication when a rapid clinical response is an urgent priority, and may augment outcomes in treatment-resistant illness.

Step 7: Psychosocial and family support

Drug treatment is only part of total management. Explanation and reassurance to the family, patient and family supportive care, and supportive psychotherapy across all phases are essential. A team approach is necessary given the devastating impact on families. Specialist referral is appropriate.

6. Australian-specific considerations

Clinical pearls

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What is the typical age of onset for first-episode schizophrenia?

Usually under 35 years of age. It is a neurodevelopmental disorder often foreshadowed by delayed developmental milestones.

What proportion of schizophrenia patients relapse if they stop antipsychotic medication?

The majority relapse within two years of stopping medication.

In first-episode psychosis, thought insertion is strongly associated with ___.

Schizophrenia.

What is thought blocking?

An abrupt, involuntary interruption of the stream of thought, sometimes occurring mid-sentence.

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