Late-onset psychosis — assessment and management (MEQ)

(i) Definitions and differentials. Howard consensus: late-onset schizophrenia (LOS) = onset after age 40; very-late-onset schizophrenia-like psychosis (VLOSLP) = onset after age 60. These are clinical/research constructs, not freestanding DSM-5-TR codes — map to schizophrenia spectrum, delusional disorder, or medical-cause psychosis as appropriate.^[1] Working diagnosis: VLOSLP-type primary late-life schizophrenia-like psychosis with partition/persecutory content and sensory impairment, pending organic exclusion. Differentials with discriminators: delirium (acute fluctuating attention — not the four-month primary story but still screen); dementia-related psychosis including Alzheimer and DLB (cognitive trajectory, visual hallucinations, RBD, parkinsonism); psychotic depression; substance/medication-induced; Charles Bonnet (isolated visual with ocular disease — does not fit multi-modal psychosis here); structural/medical CNS disease.^[2][3] A single distressed MoCA does not diagnose irreversible dementia.

(ii) Assessment and investigations. Risk: harm to neighbours driven by persecution, self-neglect, fire, weapons, exploitation; capacity for treatment/residence; legal status if high risk (jurisdiction-specific statutes). Collateral from family/GP/neighbours. MSE: delusions, hallucinations, thought form, affect, insight, cognition. Hearing assessment is both risk factor and treatment target.^[7] Work-up: FBC, U&E, LFT, glucose, lipids, TSH, B12/folate, calcium ± inflammatory markers; urine drug screen if indicated; ECG before antipsychotic; neuroimaging (MRI preferred) for first late-onset psychosis; escalate EEG/LP/autoimmune if red flags (seizures, fever, rapid decline, focal neurology).^[3]

(iii) Management. Non-drug: hearing aids/environment, reduce isolation, psychoeducation, carer/social supports, safety planning with neighbours/housing as appropriate, adapted psychological approaches if feasible.^[2][8] Drug example if primary VLOSLP after work-up: risperidone 0.25–0.5 mg orally daily, slow titration to lowest effective dose; alternatives olanzapine 2.5 mg or aripiprazole 2–5 mg with individualised choice. Monitoring: EPS, falls, metabolic panel, prolactin (if risperidone), QTc/cardiac symptoms, sedation. If dementia becomes the working frame, document mortality and stroke risk (Schneider meta-analysis), target symptom, and time-limited review/deprescribing plan — do not default to long-term high-dose therapy.^[4][5][8] Avoid high-potency typicals first-line in frail elderly; extreme caution if DLB features emerge.

(iv) Prognosis and follow-up. Many with VLOSLP show response at low–moderate atypical doses though residual delusions are common.^[5] Plan old-age psychiatry follow-up, physical health monitoring per schizophrenia-related guidance age-adjusted, and longitudinal cognitive re-assessment because VLOSLP cohorts have elevated rates of later dementia diagnosis — surveillance without premature permanent dementia labelling during untreated psychosis.^[6] Disposition depends on risk containment and supports.