We have located links that may give you full text access.
JOURNAL ARTICLE
RESEARCH SUPPORT, NON-U.S. GOV'T
Dimensional assessment of depressive severity in the elderly general population: psychometric evaluation of the PHQ-9 using Rasch Analysis.
Journal of Affective Disorders 2013 June
BACKGROUND: The depression module of the Patient Health questionnaire (PHQ-9) is a wide-spread self-report instrument for the assessment of depression with compelling psychometric characteristics when relying on classical test theory assumptions. This study aimed at evaluating whether the PHQ-9 may be interpreted as a dimensional scale measuring depression severity in the elderly general population using Rasch analysis with special emphasis on its unidimensional structure and differential item functioning (DIF) due to gender, age, and the presence of somatic multimorbidity.
METHODS: A representative sample of the elderly German general population (N=1631; age 60-85 years, 53.5% female) filled in the PHQ-9, a questionnaire about chronic medical conditions and a demographic data sheet. Unidimensionality and psychometric properties of the PHQ-9 were ascertained applying confirmatory factor analysis (CFA) and Rasch analysis.
RESULTS: Results revealed substantial violations of the unidimensionality of the scale: item 8 (retardation or agitation) had to be eliminated and multiple residual correlations were added. Gender-related DIF emerged for two items, and three items showed insufficient Rasch model fit.
LIMITATIONS: The large sample leads to high statistical power that might technically increase the probability of detecting model misfit or DIF. The sampling procedure leads to a possible underestimation of morbidity due to the exclusion of those elderly patients living in nursing homes.
CONCLUSIONS: Results suggest that - when applied in the elderly general population - the PHQ-9 should be interpreted in terms of a diagnostic algorithm for classificatory decisions about a DSM-IV based probable diagnosis of depression rather than as a dimensional scale.
METHODS: A representative sample of the elderly German general population (N=1631; age 60-85 years, 53.5% female) filled in the PHQ-9, a questionnaire about chronic medical conditions and a demographic data sheet. Unidimensionality and psychometric properties of the PHQ-9 were ascertained applying confirmatory factor analysis (CFA) and Rasch analysis.
RESULTS: Results revealed substantial violations of the unidimensionality of the scale: item 8 (retardation or agitation) had to be eliminated and multiple residual correlations were added. Gender-related DIF emerged for two items, and three items showed insufficient Rasch model fit.
LIMITATIONS: The large sample leads to high statistical power that might technically increase the probability of detecting model misfit or DIF. The sampling procedure leads to a possible underestimation of morbidity due to the exclusion of those elderly patients living in nursing homes.
CONCLUSIONS: Results suggest that - when applied in the elderly general population - the PHQ-9 should be interpreted in terms of a diagnostic algorithm for classificatory decisions about a DSM-IV based probable diagnosis of depression rather than as a dimensional scale.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app