The influences of psychotic symptoms on the activities of daily living of individuals with Alzheimer disease: a longitudinal analysis

Abstract

Objectives: Psychotic symptoms associated with Alzheimer Disease (AD) contribute to excess functional dependence. Longitudinal studies have generally examined the association between rates of functional decline and the occurrence of psychotic symptoms from either a single evaluation or from multiple evaluations rather than through changes in frequency and severity of symptoms. Although the presence or absence of psychotic symptoms at initial or follow-up examinations may be associated with changes in functional status, the nature of the relationship between changes in these domains cannot be inferred. We examine the association between changes in the frequency of psychotic symptoms and changes in dependence in activities of daily living (ADL) over a period ranging from 1 to 74 months (median = 17.7).

Method: Data from a cohort of 234 individuals referred to a memory clinic were analyzed using multilevel linear regression. Information on ADL, behavioral and psychological symptoms, depression, and cognition was collected.

Results: An increase in the frequency of psychotic symptoms had a unique influence on the deterioration of basic ADL, after controlling for demographic variables, changes in cognition, depression, and other behavioral and psychological symptoms (B = −.017, p = .003). However, changes in psychotic symptoms did not significantly contribute to declines in the ability to perform instrumental ADL (B = −.008, p = .439).

Conclusion: Changes in psychotic symptoms may influence basic but not instrumental ADL over time. These findings may have ramifications for studies and treatment plans for individuals with AD who demonstrate psychotic symptoms.

Keywords:

• dementia
• hallucinations
• delusions
• functional dependency
• prospective design

Acknowledgements

Michel Bédard is a Canada Research Chair in Aging and Health; he acknowledges the support of the Program (www.chairs.gc.ca).

Notes

Note: Extraction Method: Principal Axis Factoring. Rotation Method: Oblimin with Kaiser Normalization.

Bolded values denote factor loadings ≥ .50.

Note: SMMSE = Standardized Mini-Mental Status Exam; GDS = Geriatric Depression Scale; PSD = Psychotic Symptoms Dimension; RBD = Repetitive Behaviors Dimension.

^aCentered on 75 and then divided by 5.

^bCentered on 20 and then divided by 5.

^cCentered on 10 and then divided by 5.

^dCentered on 5 and then divided by 5.

^eCentered on 5 and then divided by 2.

^fCentered on 5 and then divided by 5.

^gIn the Rate of Change section, the Intercept shows the effect of Time (in months), and the other lines show the interactions of those terms with Time (i.e., time-varying variables).