General MedicineTier 1Disease (DEADMAN)

Psychiatry - psychotic disorders

Description

Spectrum: schizophrenia, schizoaffective disorder, brief psychotic disorder, delusional disorder, substance-induced psychosis, psychotic depression/mania
Core features: delusions, hallucinations, disorganised speech/behaviour, negative symptoms (avolition, alogia, flattened affect)

Schizophrenia lifetime prevalence ~0.5-1%; typical onset late adolescence-early adulthood, earlier onset in males
Substantially reduced life expectancy vs general population (cardiometabolic disease, suicide)

Dopamine hypothesis: mesolimbic hyperdopaminergia (positive symptoms), mesocortical hypodopaminergia (negative/cognitive symptoms)
Genetic predisposition (high heritability) interacting with environmental factors - obstetric complications, urban upbringing, migration, cannabis use (esp. high-potency, adolescent onset) as a modifiable risk factor
Neurodevelopmental model - subtle structural/connectivity changes predating overt illness onset

Clinical, DSM-5-TR criteria - >=1 month of active symptoms with continuous signs for 6 months for schizophrenia; shorter durations for brief/schizophreniform presentations
Exclude organic and substance-induced causes - urine drug screen, TFT, B12, calcium, autoimmune/infective screen (esp. first episode, atypical features, or rapid onset) - anti-NMDA receptor encephalitis is an important reversible mimic in young patients with rapid-onset psychosis + neurological/autonomic features
Early psychosis intervention services - first-episode psychosis has a distinct, better-prognosis management pathway

1. Acute psychosis

Antipsychotic medication - second-generation (olanzapine, risperidone, aripiprazole) generally first-line given lower extrapyramidal burden; individualise by side-effect profile
De-escalation and least restrictive environment; involuntary treatment under mental health legislation only if criteria met (risk, lack of capacity, no less restrictive alternative)

2. First-episode psychosis

Early intervention services - lower starting antipsychotic doses, intensive psychosocial support, family psychoeducation - improves long-term outcome

3. Maintenance/relapse prevention

Continue antipsychotic long-term after first episode (relapse risk very high on discontinuation); long-acting injectable formulations improve adherence
Clozapine for treatment-resistant schizophrenia (failure of two adequate antipsychotic trials) - most effective agent but requires mandatory haematological monitoring (agranulocytosis risk)
Cardiometabolic monitoring (weight, lipids, glucose) at baseline and regularly - antipsychotics carry substantial metabolic risk

4. Psychosocial

CBT for psychosis, family interventions, supported employment/education, substance use treatment (cannabis cessation)

Substance use disorder (especially cannabis, nicotine - very high comorbidity), depression, anxiety
Markedly increased cardiovascular mortality (antipsychotic metabolic effects + smoking + reduced healthcare engagement)
Suicide risk, particularly in the peri-diagnosis period and with comorbid depression/insight

Course variable - some achieve sustained remission (esp. with early intervention), others have a chronic relapsing-remitting or persistent course
Negative and cognitive symptoms drive long-term functional disability more than positive symptoms
Early, sustained treatment engagement substantially improves long-term functional outcome - the "critical period" in the first few years is prognostically important

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