Psychosis in dementia — delusions, hallucinations, paranoid ideation — affects substantial proportions of dementia patients (particularly common in Lewy body dementia and middle-to-late stage Alzheimer's). The clinical approach involves distinguishing distressing or dangerous psychosis warranting treatment from psychotic phenomena that the patient is not distressed by, addressing reversible contributors, and using antipsychotic medications selectively with attention to their substantial adverse effect profile in this population.
The recognition and characterization. Delusions in dementia — particularly common are theft delusions (someone is stealing belongings — frequently reflecting forgetting where items were placed), delusion of misidentification (Capgras-like — believing family member is impostor), persecutory delusions, infidelity delusions. Hallucinations — visual hallucinations particularly characteristic of Lewy body dementia; auditory hallucinations more common in delirium superimposed on dementia. Differential includes delirium (acute, fluctuating, reversible contributors), late-onset primary psychosis (rare), and dementia-related psychosis.
Lewy body dementia specifically. Visual hallucinations are part of the diagnostic criteria and frequently appear early. These are often non-distressing for the patient initially (familiar people, animals). Cholinesterase inhibitors (donepezil, rivastigmine — Stage 18.3) frequently improve hallucinations in DLB substantially. Pimavanserin has FDA approval for PD psychosis and is increasingly used in DLB. Antipsychotic sensitivity is profound in DLB — typical antipsychotics produce severe extrapyramidal effects; quetiapine and clozapine are options if antipsychotic needed but use cautiously.
The antipsychotic black box warning and clinical reality. The mortality warning for antipsychotics in elderly dementia patients reflects real data — modestly increased mortality (HR ~1.5-1.7) primarily through cardiovascular and cerebrovascular events. The risk is meaningful but should not absolutely preclude use when the clinical situation warrants. Selective use with informed consent is appropriate. Risperidone, olanzapine, aripiprazole, brexpiprazole each have varying evidence; brexpiprazole's specific FDA approval for AD agitation (Stage 25.2) extends to associated psychotic features.
The clinical decision framework. Address reversible contributors (delirium, medications, infection). Determine whether psychosis is distressing to patient or causing safety concerns — non-distressing visual hallucinations in DLB may not warrant treatment. Try non-pharmacological approaches — addressing triggers, validation, reassurance, environmental modifications. If antipsychotic indicated: lowest effective dose, time-limited use with periodic reassessment, informed consent about mortality warning, monitoring for adverse effects. Discontinue or taper when possible. The discipline is to recognize psychosis in dementia as substantive clinical entity, address reversible contributors, use antipsychotics selectively when warranted with informed consent and monitoring, and integrate with broader BPSD and dementia care.