The Older Adult with New Psychosis
Mrs. T, 78, lives alone and is brought in by her daughter, who reports three weeks of worsening confusion, visual hallucinations of "men in the yard," and one episode of her mother striking her. Mrs. T has hypertension, type 2 diabetes, and osteoarthritis. Her medications are lisinopril, metformin, hydrochlorothiazide, and oxybutynin, and she recently started diphenhydramine for sleep. She has no prior psychiatric history. On exam she is alert but disoriented to date and place, with fluctuating attention; she has a mild resting tremor and reduced arm swing on the right. She is afebrile, and her daughter denies any recent falls or head trauma.
1. What is your differential, and what workup do you order?
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New psychosis in a 78-year-old is delirium or a medical/neuropsychiatric cause until proven otherwise - not primary psychiatric illness.
Differential:
- Delirium (fluctuating attention, visual hallucinations, acute onset) - from anticholinergic burden (oxybutynin + diphenhydramine), infection (UTI), metabolic derangement, or medication toxicity.
- Dementia with Lewy bodies - visual hallucinations, parkinsonism (tremor, reduced arm swing), fluctuating cognition. Critical: avoid typical antipsychotics (severe sensitivity).
- Parkinson disease dementia - similar picture.
- Vascular dementia / stroke - stepwise decline, focal findings.
- Metabolic: hyperglycemia, hyponatremia (HCTZ), renal impairment.
- Other: infection, subdural hematoma (even without reported trauma), medication effect.
Workup: CBC, CMP (glucose, sodium, renal function), urinalysis and culture, TSH, B12, ECG, and neuroimaging (CT head). Review all medications. Consider cognitive testing once delirium resolves.
2. What medication changes do you make, and what do you avoid?
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Stop the anticholinergic burden first:
- Discontinue diphenhydramine - strongly anticholinergic, causes delirium, and is inappropriate in older adults (Beers criteria).
- Discontinue or replace oxybutynin - also strongly anticholinergic; discuss alternatives with her PCP (e.g., behavioral measures, or a less anticholinergic agent such as mirabegron if appropriate).
Avoid:
- Typical antipsychotics (haloperidol) if DLB is suspected - risk of severe neuroleptic sensitivity, rigidity, and death. Use cautiously and at low doses only if needed for dangerous agitation.
- Benzodiazepines - worsen delirium and falls.
If antipsychotic is needed for severe agitation/psychosis: use the lowest dose of quetiapine or another agent with caution, with informed consent from the daughter (if decision-making capacity is impaired) and close monitoring.
Treat the cause: hydration, treat infection, correct electrolytes, review all medications. Reassess cognition after delirium clears.
3. The daughter asks about capacity and whether her mother can still live alone. How do you address this?
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Capacity is decision-specific and time-specific, not global.
- Assess the four elements for the specific decision (e.g., living alone, managing medications): understanding, appreciation, reasoning, and expressing a choice.
- Delirium complicates capacity - capacity may be temporarily impaired and should be reassessed after the delirium resolves.
- If she lacks capacity for a specific decision: identify the appropriate surrogate decision-maker under state law (health care proxy, guardian, or default surrogate) and follow substituted judgment/best interests.
- Living alone: Given disorientation, hallucinations, and an episode of aggression, independent living is unsafe right now. Discuss a temporary supervised arrangement (stay with daughter, home health, or short-term placement) with reassessment after treatment.
- Safety: medication management, driving, cooking, and fall risk must be addressed; consider a home safety evaluation.
- Document the capacity assessment, the surrogate, and the plan; involve social work and, if needed, adult protective services if neglect or abuse is a concern.