A1 Refereed original research article in a scientific journal
Factorial Structure and Validity of Depression (PHQ-9) and Anxiety (GAD-7) Scales after Traumatic Brain Injury
Authors: Teymoori A, Gorbunova A, Haghish FE, Real R, Zeldovich M, Wu YJ, Polinder S, Asendorf T, Menon D, von Steinbuechel N; CENTER-TBI Investigators and Participants
Publisher: MDPI
Publication year: 2020
Journal: Journal of Clinical Medicine
Journal name in source: JOURNAL OF CLINICAL MEDICINE
Journal acronym: J CLIN MED
Article number: ARTN 873
Volume: 9
Issue: 3
Number of pages: 21
eISSN: 2077-0383
DOI: https://doi.org/10.3390/jcm9030873
Web address : https://www.mdpi.com/2077-0383/9/3/873
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/52216559
Background: The dimensionality of depression and anxiety instruments have recently been a source of controversy. Objectives and Design: In a European-wide sample of patients after Traumatic Brain Injury (TBI), we aim to examine the factorial structure, validity, and association of the Patient Health Questionnaire for depression (PHQ-9) and the Generalized Anxiety Disorder (GAD-7) instruments. This study is based on longitudinal observational data. We conducted analyses of factorial structure and discriminant validity of outcomes six-months after TBI. We also examined the prevalence, co-occurrence, and changes of scores on the PHQ-9 and GAD-7 at 3-, 6-, and 12-month post-TBI assessments. Participants: At six-months post-TBI assessment, 2137 (738 (34.5%) women) participants completed the PHQ-9 and GAD-7 questionnaires. For the longitudinal analysis, we had 1922 participants (672 (35.0%) women). Results: The results of exploratory factor analysis suggested a general latent construct underlying both PHQ-9 and GAD-7 measures. Confirmatory factor analyses showed a slight improvement in the fit indices for the bifactorial model. The Omega hierarchical test clearly differentiated two subfactors of PHQ-9 and GAD-7 items over and above the underlying general factor; however, most of the variance (85.0%) was explained by the general factor and the explained variance of the subfactors was small. The PHQ-9 and GAD-7 performed similarly in detecting post-traumatic stress disorder (PTSD). As defined by conventional cut-offs, depression and anxiety have different prevalence rates in the sample. The scales also differed in their relationships with the short form of health survey (SF-36v2) subscales. The longitudinal analysis showed high stability of depression and anxiety symptoms: 49-67% of the post-TBI patients with comorbid depression and anxiety reported the persistence of the symptoms over time. Discussion: The factorial structure analysis favors a general latent construct underlying both depression and anxiety scales among patients after TBI. We discuss the implications our findings and future research directions.
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