Measurement invariance of the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7) across four European countries during the COVID-19 pandemic

Mark Shevlin; Sarah Butter; Orla McBride; Jamie Murphy; Jilly Gibson-Miller; Todd K Hartman; Liat Levita; Liam Mason; Anton P Martinez; Ryan McKay; Thomas Va Stocks; Kate M Bennett; Philip Hyland; Frédérique Vallieres; Carmen Valiente; Carmelo Vazquez; Alba Contreras; Vanesa Peinado; Almudena Trucharte; Marco Bertamini; Anna Panzeri; Giovanni Bruno; Umberto Granziol; Giuseppe Mignemi; Andrea Spoto; Giulio Vidotto; Richard P Bentall

doi:10.1186/s12888-022-03787-5

Measurement invariance of the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7) across four European countries during the COVID-19 pandemic

BMC Psychiatry. 2022 Mar 1;22(1):154. doi: 10.1186/s12888-022-03787-5.

Authors

Mark Shevlin¹, Sarah Butter², Orla McBride¹, Jamie Murphy¹, Jilly Gibson-Miller³, Todd K Hartman⁴, Liat Levita³, Liam Mason⁵, Anton P Martinez³, Ryan McKay⁶, Thomas Va Stocks³, Kate M Bennett⁷, Philip Hyland⁸, Frédérique Vallieres⁹, Carmen Valiente¹⁰, Carmelo Vazquez¹⁰, Alba Contreras¹⁰, Vanesa Peinado¹⁰, Almudena Trucharte¹⁰, Marco Bertamini⁷, Anna Panzeri¹¹, Giovanni Bruno¹¹, Umberto Granziol¹¹, Giuseppe Mignemi¹¹, Andrea Spoto¹¹, Giulio Vidotto¹¹, Richard P Bentall³

Affiliations

¹ Ulster University, Coleraine, Northern Ireland.
² Department of Psychology, University of Sheffield, Cathedral Court, 1 Vicar Lane, S1 2LT, Sheffield, England. s.butter@sheffield.ac.uk.
³ Department of Psychology, University of Sheffield, Cathedral Court, 1 Vicar Lane, S1 2LT, Sheffield, England.
⁴ University of Manchester, Manchester, England.
⁵ University College London, London, England.
⁶ Royal Holloway, University of London, Egham, England.
⁷ University of Liverpool, Liverpool, England.
⁸ Maynooth University, Maynooth, Ireland.
⁹ Trinity College Dublin, Dublin, Ireland.
¹⁰ Complutense University of Madrid, Madrid, Spain.
¹¹ University of Padua, Padua, Italy.

Abstract

Background: The Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7) are self-report measures of major depressive disorder and generalised anxiety disorder. The primary aim of this study was to test for differential item functioning (DIF) on the PHQ-9 and GAD-7 items based on age, sex (males and females), and country.

Method: Data from nationally representative surveys in UK, Ireland, Spain, and Italy (combined N = 6,054) were used to fit confirmatory factor analytic and multiple-indictor multiple-causes models.

Results: Spain and Italy had higher latent variable means than the UK and Ireland for both anxiety and depression, but there was no evidence for differential items functioning.

Conclusions: The PHQ-9 and GAD-7 scores were found to be unidimensional, reliable, and largely free of DIF in data from four large nationally representative samples of the general population in the UK, Ireland, Italy and Spain.

Keywords: Anxiety; Depression; GAD-7; Measurement invariance; PHQ-9.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anxiety
COVID-19* / epidemiology
Depression
Depressive Disorder, Major* / diagnosis
Depressive Disorder, Major* / epidemiology
Female
Humans
Male
Pandemics
Patient Health Questionnaire
Psychometrics
SARS-CoV-2
Surveys and Questionnaires