@article{ref1,
title="Factorial structure and validity of Depression (PHQ-9) and Anxiety (GAD-7) scales after traumatic brain injury",
journal="Journal of clinical medicine",
year="2020",
author="Teymoori, Ali and Gorbunova, Anastasia and Haghish, Fardzadeh E. and Real, Ruben and Zeldovich, Marina and Wu, Yi-Jhen and Polinder, Suzanne and Asendorf, Thomas and Menon, David and Center-Tbi Investigators And Participants,  and Steinbüchel, Nicole V.",
volume="9",
number="3",
pages="e873-e873",
abstract="BACKGROUND: The dimensionality of depression and anxiety instruments have recently been a source of controversy. <br><br>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). <br><br>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. <br><br>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.<p /> <p>Language: en</p>",
language="en",
issn="2077-0383",
doi="10.3390/jcm9030873",
url="http://dx.doi.org/10.3390/jcm9030873"
}