Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample
Abstract Objective The aim of this study was to test factor structure, measurement invariance, and concurrent validity of the nine item Patient Health Questionnaire-9 (PHQ-9) and the seven item Generalized Anxiety Disorder scale-7 (GAD-7) in a heterogeneous outpatient sample. Method Outpatients comp...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2022-07-01
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| Series: | BMC Psychiatry |
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| Online Access: | https://doi.org/10.1186/s12888-022-04101-z |
| _version_ | 1828756791372021760 |
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| author | Martin Brattmyr Martin Schevik Lindberg Stian Solem Odin Hjemdal Audun Havnen |
| author_facet | Martin Brattmyr Martin Schevik Lindberg Stian Solem Odin Hjemdal Audun Havnen |
| author_sort | Martin Brattmyr |
| collection | DOAJ |
| description | Abstract Objective The aim of this study was to test factor structure, measurement invariance, and concurrent validity of the nine item Patient Health Questionnaire-9 (PHQ-9) and the seven item Generalized Anxiety Disorder scale-7 (GAD-7) in a heterogeneous outpatient sample. Method Outpatients completed the PHQ-9, GAD-7, and the Working Social Adjustment Scale (WSAS) before starting treatment. Study design was cross-sectional, with convenience sampling. The total sample consisted of 831 participants (61% women). Results Both PHQ-9 and GAD-7 demonstrated better fit statistics with two-factor and bifactor solutions consisting of a cognitive and somatic factor. Omega hierarchical was .78 for PHQ-9 and .81 for GAD-7. Both instruments achieved scalar invariance across gender, diagnosis, and comorbidity. However, the somatic factors demonstrated poor discriminant validity. These factors are not well separatable and risks being too similar if used together. The general factors of both instruments were most associated with functional impairment, although PHQ-9 demonstrated a stronger association with WSAS (γ = .74, r 2 = .62) than GAD-7 (γ = .54, r 2 = .32). Using latent mean difference, women and patients with comorbidity had significantly higher scores of both depression and anxiety. Conclusion This study shows that the PHQ-9 and GAD-7 may be used as one-dimensional instruments in clinical settings. Tests for measurement invariance supported that both measures are understood and interpreted comparably across gender and diagnostic subgroups. |
| first_indexed | 2024-12-10T23:21:54Z |
| format | Article |
| id | doaj.art-44df596ecc7443a685d074d020db9523 |
| institution | Directory Open Access Journal |
| issn | 1471-244X |
| language | English |
| last_indexed | 2024-12-10T23:21:54Z |
| publishDate | 2022-07-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Psychiatry |
| spelling | doaj.art-44df596ecc7443a685d074d020db95232022-12-22T01:29:41ZengBMCBMC Psychiatry1471-244X2022-07-0122111110.1186/s12888-022-04101-zFactor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sampleMartin Brattmyr0Martin Schevik Lindberg1Stian Solem2Odin Hjemdal3Audun Havnen4Department of Psychology, Norwegian University of Science and TechnologyDepartment of Psychology, Norwegian University of Science and TechnologyDepartment of Psychology, Norwegian University of Science and TechnologyDepartment of Psychology, Norwegian University of Science and TechnologyDepartment of Psychology, Norwegian University of Science and TechnologyAbstract Objective The aim of this study was to test factor structure, measurement invariance, and concurrent validity of the nine item Patient Health Questionnaire-9 (PHQ-9) and the seven item Generalized Anxiety Disorder scale-7 (GAD-7) in a heterogeneous outpatient sample. Method Outpatients completed the PHQ-9, GAD-7, and the Working Social Adjustment Scale (WSAS) before starting treatment. Study design was cross-sectional, with convenience sampling. The total sample consisted of 831 participants (61% women). Results Both PHQ-9 and GAD-7 demonstrated better fit statistics with two-factor and bifactor solutions consisting of a cognitive and somatic factor. Omega hierarchical was .78 for PHQ-9 and .81 for GAD-7. Both instruments achieved scalar invariance across gender, diagnosis, and comorbidity. However, the somatic factors demonstrated poor discriminant validity. These factors are not well separatable and risks being too similar if used together. The general factors of both instruments were most associated with functional impairment, although PHQ-9 demonstrated a stronger association with WSAS (γ = .74, r 2 = .62) than GAD-7 (γ = .54, r 2 = .32). Using latent mean difference, women and patients with comorbidity had significantly higher scores of both depression and anxiety. Conclusion This study shows that the PHQ-9 and GAD-7 may be used as one-dimensional instruments in clinical settings. Tests for measurement invariance supported that both measures are understood and interpreted comparably across gender and diagnostic subgroups.https://doi.org/10.1186/s12888-022-04101-zPHQ-9GAD-7Factor structureMeasurement invarianceReliabilityValidity |
| spellingShingle | Martin Brattmyr Martin Schevik Lindberg Stian Solem Odin Hjemdal Audun Havnen Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample BMC Psychiatry PHQ-9 GAD-7 Factor structure Measurement invariance Reliability Validity |
| title | Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample |
| title_full | Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample |
| title_fullStr | Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample |
| title_full_unstemmed | Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample |
| title_short | Factor structure, measurement invariance, and concurrent validity of the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder scale-7 in a Norwegian psychiatric outpatient sample |
| title_sort | factor structure measurement invariance and concurrent validity of the patient health questionnaire 9 and the generalized anxiety disorder scale 7 in a norwegian psychiatric outpatient sample |
| topic | PHQ-9 GAD-7 Factor structure Measurement invariance Reliability Validity |
| url | https://doi.org/10.1186/s12888-022-04101-z |
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