psychosis in Alzheimer's disease

Introduction

Also see psychosis & agitation in the elderly

Epidemiology

• prevalence rate for psychosis in patients with Alzheimer disease is ~50%.
• it is most common in the middle stages of the disease

History

• no prior history of psychosis

Clinical manifestations

• visual hallucinations are more common than auditory hallucinations
• hallucinations usually involve people from the past (dead relatives), intruders, animals, or objects
• hallucinations generally occur in mid-stage Alzheimer's disease
• delusions typically involve beliefs of theft, infidelity, abandonment, not living in their home, & persecutions
• lack of bizarre or complex delusions
• delusions decrease in later stages of disease
• cognitive impairment & other manifestations of Alzheimer's disease

Diagnostic criteria

• presence of hallucinations (intermittent or continual), delusions, or both, of >= 1 month duration that disrupts the life of the patient or others
• psychosis cannot be attributable to delirium, drug effects, schizophrenia, or other psychiatric disorder
• background of cognitive impairment consistent with Alzheimer's disease

Differential diagnosis

• late onset schizophrenia
  • bizarre or complex delusions,
  • prior history of psychosis
  • more frequent auditory hallucinations
  • cognition may be unimpaired
• psychosis in Alzheimer's disease
  • more frequent visual hallucinations
  • cognitive impairment
  • shuffling gair
• dementia with Lewy bodies
  • rigidity
  • parkinsonian gait (festination, retropulsion, & en bloc turning)

Management

• nonpharmacologic interventions are 1st line
• when these fail, risperidone, olanzapine, & aripiprazole are most effective for aggression, anger, & paranoia but may be associated with significant morbidity & mortality

More general terms

• psychosis
• Alzheimer's disease (ADD)

Additional terms

• psychosis, agitation & difficult behavior in the elderly