Regular Research Article
Psychosis of Alzheimer Disease: Prevalence, Incidence, Persistence, Risk Factors, and Mortality

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Objectives

To establish the prevalence, incidence, persistence, risk factors, and mortality risk increase of psychosis of Alzheimer disease (PoAD) in a clinical sample.

Design, participants, and measurements

Cross-sectional, observational study of 491 patients with probable AD who, at baseline visit, were evaluated with the Cambridge Examination for Mental Disorders of the Elderly, the Neuropsychiatric Inventory–10, the Rapid Disability Rating Scale–2, and the Zarit Burden Interview. All participants were reevaluated at 6, 12, 18, and 24 months. PoAD diagnoses were made using specific criteria.

Results

PoAD prevalence was 7.3%, and the cumulative incidence at 6, 12, 18, and 24 months was 5.8%, 10.6%, 13.5%, and 15.1%, respectively. After 1 year, psychotic symptoms persisted in 68.7% of the patients with initial PoAD. At baseline, patients with PoAD scored lower in the Cambridge Cognitive Examination and Mini-Mental State Examination and higher in the Rapid Disability Rating Scale–2 and Zarit Burden Interview tests. Both low scores in the Cambridge Cognitive Examination subscale of learning memory (hazard ratio [HR] = 0.874; 95% CI: 0.788–0.969; Wald χ2 = 6.515; df = 1) and perception (HR = 0.743; 95% CI: 0.610–0.904; Wald χ2 = 8.778; df = 1), and high scores in expressive language (HR = 1.179; 95% CI: 1.024–1.358; Wald χ2 = 5.261; df = 1) and calculation skills (HR = 1.763; 95% CI: 1.067–2.913; Wald χ2 = 4.905; df = 1) were found to be associated with PoAD. PoAD leads to a faster functional impairment, and it increases mortality risk (HR = 2.191; 95% CI: 1.136–4.228; Wald χ2 = 5.471; df = 1) after controlling for age, gender, cognitive and functional disability, general health status, and antipsychotic treatment.

Conclusions

PoAD seems to define a phenotype of AD of greater severity, with worsened functional progression and increased mortality risk.

Section snippets

Study Design

Cohort study with cross-sectional and longitudinal components.

Results

The sample consisted of 491 patients, of whom 70.9% (n = 348) were women and 40.1% (n = 197) were younger than 75 years (mean: 75.2 years; SD: 6.6 years; range: 52–89 years). The mean number of years of education was 5.9 (SD: 3.7; range: 0–21). The mean score on the CAMCOG was 55.6 points (SD: 13.4; range: 14–88) and 10.1 points for the NPI (SD: 11.4; range: 0–77). The mean time since dementia onset was 32.5 months (SD: 27.4; range: 2–170), and 25.6% (n = 126) of the subjects had a history of a

Conclusions

Questions exist regarding the homogeneity of PoAD, because subgroups of patients with psychotic symptoms have been observed to have different characteristics regarding the kind of psychotic symptoms and other clinical variables.25 The differences observed in patients with delusions and without hallucinations and patients with hallucinations2 give rise to questions regarding the validity of PoAD. Note that varied clinical situations may be observed, all of which include psychotic symptoms that

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