Concurrent validity of neuropsychiatric subgroups on caregiver burden in Alzheimer disease patients.

Objective: In a previously published study, the authors conceptualized neuropsychiatric symptoms in Alzheimer disease (AD) patients as distinct symptom profiles with differential outcomes. In the present study, our aim was to further examine the validation of the classification by considering its concurrent validity on caregiver burden.
Method: As described previously, neuropsychiatric symptoms, as assessed by the Neuropsychiatric Inventory, in 122 patients with AD were categorized, using cluster analysis. The presence as well as the severity and frequency of symptoms were both used in the classification. After the classification, group differences in caregiver burden, as measured by Screen for Caregiver Burden, were tested using analysis of covariance. The effects of important covariates, such as functional impairment, comorbid medical conditions, parkinsonism, age, and cognitive functioning, were examined.
Results: Based on the presence of symptoms, subgroups differed in the level of caregiver distress in that caregivers of the "minimally symptomatic" and the "affective/apathetic" subgroups experienced less distress than the caregivers of the "highly symptomatic" subgroup. Based on the severity and frequency of symptoms, subgroups differed in such a way that caregivers of the "minimally symptomatic" and the "predominantly apathetic" subgroups endorsed less distress than the caregivers of the "affective" and the "highly symptomatic" subgroups.
Conclusion: Neuropsychiatric subgroups were able to differentially predict caregiver burden. The findings appear to lend further support to the validity of classifying neuropsychiatric symptoms in AD patients using cluster analysis.