We compared the psychometric performance of two validated self-report anxiety symptom measures when rated by people with dementia versus collaterals (as proxies). Forty-one participants with mild-to-moderate dementia and their respective collaterals completed the Geriatric Anxiety Inventory, the Penn State Worry Questionnaire-Abbreviated, and a structured diagnostic interview. We used descriptive and nonparametric statistics to compare scores according to respondent characteristics. Receiver operating characteristic (ROC) curves were calculated to establish the predictive validity of each instrument by rater type against a clinical diagnosis of an anxiety disorder. Participant and collateral ratings performed comparably for both instruments. However, collaterals tended to give more severe symptom ratings, and the best-performing cut-off scores were higher for collaterals. Our findings suggest that people with mild-to-moderate dementia can give reliable self-reports of anxiety symptoms, with validity comparable to reports obtained from collaterals. Scores obtained from multiple informants should be interpreted in context.
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