Delamain, H;
Buckman, JEJ;
Stott, J;
John, A;
Singh, S;
Pilling, S;
Saunders, R;
(2024)
Measurement invariance and differential item functioning of the PHQ-9 and GAD-7 between working age and older adults seeking treatment for common mental disorders.
Journal of Affective Disorders
, 347
pp. 15-22.
10.1016/j.jad.2023.11.048.
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Abstract
Background: The nine-item Patient Health Questionnaire (PHQ-9) and seven-item Generalised Anxiety Disorder (GAD-7) scale are widely used clinically and within research, and so it is important to determine how the measures, and individual items within the measures, are answered by adults of differing ages. This study sought to evaluate measurement invariance and differential item functioning (DIF) of the PHQ-9 and GAD-7 between working age and older adults seeking routine psychological treatment. // Methods: Data of working age (18–64 years old) and older (≥65) adults in eight Improving Access to Psychological Therapies (IAPT) services were used. Confirmatory factor analysis (CFA) was used to establish unidimensionality of the PHQ-9 and GAD-7, with multiple-group CFA to test measurement invariance and The Multiple Indicators, Multiple Causes Models approach to assess DIF. The employed methods were applied to a propensity score matched (PSM) sample in sensitivity analyses to control for potential confounding. // Results: Data from 166,816 patients (159,325 working age, 7491 older) were used to show measurement invariance for the PHQ-9 and GAD-7, with limited evidence of DIF and similar results found with a PSM sample (n = 5868). // Limitations: The localised sample creates an inability to detect geographical variance, and the potential effect of unmeasured confounders cannot be ruled out. // Conclusions: The findings support the use of the PHQ-9 and GAD-7 measures for working age and older adults, both clinically and in research settings. This study validates using the measures for these age groups to assess clinically significant symptom thresholds, and monitor treatment outcomes between them.
| Type: | Article |
|---|---|
| Title: | Measurement invariance and differential item functioning of the PHQ-9 and GAD-7 between working age and older adults seeking treatment for common mental disorders |
| Location: | Netherlands |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.jad.2023.11.048 |
| Publisher version: | https://doi.org/10.1016/j.jad.2023.11.048 |
| Language: | English |
| Additional information: | Copyright © 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Measurement invariance; Differential item functioning; GAD-7; PHQ-9; Older adults |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences > Clinical, Edu and Hlth Psychology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10182393 |
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