Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample

BackgroundThe Patient Health Questionnaire (PHQ-9) is a popular tool for assessing depressive symptoms in both general and clinical populations. The present study used a large representative sample of the German adult population to confirm desired psychometric functioning and to provide updated popu...

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Main Authors: Sören Kliem, Cedric Sachser, Anna Lohmann, Dirk Baier, Elmar Brähler, Harald Gündel, Jörg M. Fegert
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-12-01
Series:Frontiers in Psychiatry
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Online Access:https://www.frontiersin.org/articles/10.3389/fpsyt.2024.1483782/full
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author Sören Kliem
Cedric Sachser
Anna Lohmann
Dirk Baier
Elmar Brähler
Elmar Brähler
Harald Gündel
Jörg M. Fegert
author_facet Sören Kliem
Cedric Sachser
Anna Lohmann
Dirk Baier
Elmar Brähler
Elmar Brähler
Harald Gündel
Jörg M. Fegert
author_sort Sören Kliem
collection DOAJ
description BackgroundThe Patient Health Questionnaire (PHQ-9) is a popular tool for assessing depressive symptoms in both general and clinical populations. The present study used a large representative sample of the German adult population to confirm desired psychometric functioning and to provide updated population norms.MethodsThe following psychometric properties were assessed: (i) Item characteristics (item means, standard deviations and inter-item correlations), (ii) Construct validity (correlations of the PHQ-9 sum-score with scores obtained from instruments assessing depression, anxiety and somatization (GAD-7, BSI-18), (iii) Internal consistency (coefficient omega), (iv) Factorial validity (via confirmatory factor analysis of the assumed one factorial model) as well as (v) Measurement invariance (via multi-group confirmatory factor analyses across gender, age, income and education).ResultsThe study found that the PHQ-9 had sound psychometric properties in terms of internal consistency and construct validity, and that measurements obtained with the tool could be compared across gender and age.LimitationsDespite using a representative sample, the response rate was only 42.6%. Furthermore, diagnostic efficiency cannot be assessed as there were no clinical interviews conducted. Conclusion: The updated population based norms, which are presented for the total sample as well as separated by gender and various age-groups, provide a useful reference for clinical practice and epidemiological research.
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spelling doaj-art-fbf2a9c543344543b2ed52ae52970a3f2024-12-12T15:24:37ZengFrontiers Media S.A.Frontiers in Psychiatry1664-06402024-12-011510.3389/fpsyt.2024.14837821483782Psychometric evaluation and community norms of the PHQ-9, based on a representative German sampleSören Kliem0Cedric Sachser1Anna Lohmann2Dirk Baier3Elmar Brähler4Elmar Brähler5Harald Gündel6Jörg M. Fegert7Department of Social Welfare, Ernst-Abbe-Hochschule Jena - University of Applied Sciences, Jena, GermanyDepartment for Child and Adolescent Psychiatry/Psychotherapy, University Clinic for Psychosomatic Medicine and Psychotherapy Ulm, Ulm, GermanyDepartment of Social Welfare, Ernst-Abbe-Hochschule Jena - University of Applied Sciences, Jena, GermanyInstitute of Delinquency and Crime Prevention, Zurich University of Applied Sciences, Zurich, SwitzerlandDepartment of Psychosomatic Medicine and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, GermanyDepartment of Psychosomatic Medicine and Psychotherapy, Ulm University Medical Center, Ulm, GermanyDepartment of Psychosomatic Medicine and Psychotherapy, Ulm University Medical Center, Ulm, GermanyDepartment for Child and Adolescent Psychiatry/Psychotherapy, University Clinic for Psychosomatic Medicine and Psychotherapy Ulm, Ulm, GermanyBackgroundThe Patient Health Questionnaire (PHQ-9) is a popular tool for assessing depressive symptoms in both general and clinical populations. The present study used a large representative sample of the German adult population to confirm desired psychometric functioning and to provide updated population norms.MethodsThe following psychometric properties were assessed: (i) Item characteristics (item means, standard deviations and inter-item correlations), (ii) Construct validity (correlations of the PHQ-9 sum-score with scores obtained from instruments assessing depression, anxiety and somatization (GAD-7, BSI-18), (iii) Internal consistency (coefficient omega), (iv) Factorial validity (via confirmatory factor analysis of the assumed one factorial model) as well as (v) Measurement invariance (via multi-group confirmatory factor analyses across gender, age, income and education).ResultsThe study found that the PHQ-9 had sound psychometric properties in terms of internal consistency and construct validity, and that measurements obtained with the tool could be compared across gender and age.LimitationsDespite using a representative sample, the response rate was only 42.6%. Furthermore, diagnostic efficiency cannot be assessed as there were no clinical interviews conducted. Conclusion: The updated population based norms, which are presented for the total sample as well as separated by gender and various age-groups, provide a useful reference for clinical practice and epidemiological research.https://www.frontiersin.org/articles/10.3389/fpsyt.2024.1483782/fullPHQ-9major depressionself-report questionnairepopulation normspsychometricsmeasurement invariance
spellingShingle Sören Kliem
Cedric Sachser
Anna Lohmann
Dirk Baier
Elmar Brähler
Elmar Brähler
Harald Gündel
Jörg M. Fegert
Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample
Frontiers in Psychiatry
PHQ-9
major depression
self-report questionnaire
population norms
psychometrics
measurement invariance
title Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample
title_full Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample
title_fullStr Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample
title_full_unstemmed Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample
title_short Psychometric evaluation and community norms of the PHQ-9, based on a representative German sample
title_sort psychometric evaluation and community norms of the phq 9 based on a representative german sample
topic PHQ-9
major depression
self-report questionnaire
population norms
psychometrics
measurement invariance
url https://www.frontiersin.org/articles/10.3389/fpsyt.2024.1483782/full
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