Abstract
This study examined the psychometric properties of the Generalized Anxiety Disorder Scale-7 (GAD-7) in a sample of 536 outpatients presenting at a specialty clinic for anxiety and mood disorders. A confirmatory factor analysis (CFA) was used to test the unidimensionality of the GAD-7. This model did not fit the data well. The CFA solution was respecified correlating residuals among items assessing somatic symptoms. This respecified model fit the data well. A series of multiple-groups CFAs determined that the measurement properties of the GAD-7 were invariant between sexes. Scale reliability estimates of the GAD-7 were favorable for the full sample, and for males and females. Sensitivity and specificity could not be balanced at any cut-point. Findings attest to the value of this instrument as a dimensional indicator of GAD severity rather than a screening tool for the presence or absence of the disorder in outpatients with anxiety and mood disorders.
Similar content being viewed by others
Notes
To address this issue, we tested the relationship between the GAD-7 and high negative affect/neuroticism using the Neuroticism scale from the NEO Five Factor Inventory (NFFI-N). Although the NFFI-N was moderately correlated with the GAD-7 factor (r = .56), inferential tests of the differential magnitude of relationships indicated that the GAD-7 factor was more strongly correlated with the DASS-S (r = .68, z = 4.50, p < .001) and the PSWQ (r = .66, z = 3.93, p < .001) than the NFFI-N. Although providing support for the convergent validity of the GAD-7, the results also indicated that the GAD-7 factor was more strongly correlated with the NFFI-N than with the DASS-D (r = .47, z = 2.97, p < .01) and the OCD-R (r = .42, z = 3.40, p < .001) in accord with the notion that GAD is more closely related to neuroticism than other emotional disorders (e.g., major depressive disorder, OCD). The test of the differential magnitude of correlations involving the GAD-7 and NFFI-N with the DASS-A was not significant (r = .52, z = 0.85).
References
Abramowitz, J. S., & Deacon, B. J. (2006). Psychometric properties and construct validity of the Obsessive-Compulsive Inventory—Revised: replication and extension with a clinical sample. Journal of Anxiety Disorders, 20, 1016–1035.
Abramowitz, J. S., & Foa, E. B. (1998). Worries and obsessions in individuals with obsessive–compulsive disorder with and without comorbid generalized anxiety disorder. Behaviour Research and Therapy, 36, 695–700.
Beard, C., & Björgvinsson, T. (2014). Beyond generalized anxiety disorder: psychometric properties of the GAD-7 in a heterogeneous psychiatric sample. Journal of Anxiety Disorders, 28, 547–552.
Brown, T. A. (2003). Confirmatory factor analysis of the Penn State Worry Questionnaire: multiple factors or method effects? Behaviour Research and Therapy, 41, 1411–1426.
Brown, T. A. (2015). Confirmatory factor analysis for applied research (2nd ed.). New York: Guilford Press.
Brown, T. A., & Barlow, D. H. (2009). A proposal for a dimensional classification system based on the shared features of the DSM-IV anxiety and mood disorders: implications for assessment and treatment. Psychological Assessment, 21, 256–271.
Brown, T.A., Antony, M. M., & Barlow, D.H . (1992). Psychometric properties of the Penn State Worry Questionnaire in a clinical anxiety disorders sample. Behaviour Research and Therapy, 30(1), 33–7.
Brown T. A., Chorpita B. F., Korotitsch, W., & Barlow, D. H. (1997). Psychometric properties of the Depression Anxiety Stress Scales (DASS) in clinical samples. Behaviour Research and Therapy, 30 35(1),79–89.
Brown, T. A., Campbell, L. A., Lehman, C. L., Grisham, J. R., & Mancill, R. B. (2001). Current and lifetime comorbidity of the DSM-IV anxiety and mood disorders in a large clinical sample. Journal of Abnormal Psychology, 110, 585–599.
Dear, B. F., Titov, N., Sunderland, M., McMillan, D., Anderson, T., Lorian, C., & Robinson, E. (2011). Psychometric comparison of the Generalized Anxiety Disorder Scale-7 and the Penn State Worry Questionnaire for measuring response during treatment of generalised anxiety disorder. Cognitive Behaviour Therapy, 40, 216–227.
Delgadillo, J., Payne, S., Gilbody, S., Godfrey, C., Gore, S., Jessop, D., & Dale, V. (2012). Brief case finding tools for anxiety disorders: validation of GAD-7 and GAD-7 in addictions treatment. Drug and Alcohol Dependence, 125, 37–42.
Di Nardo, P. A., Brown, T. A., & Barlow, D. H. (1994). Anxiety Disorder Interview Schedule for DSM-IV: Lifetime version (ADIS-IV-L). New York: Oxford University Press.
Donker, T., van Straten, A., Marks, I., & Cuijpers, P. (2011). Quick and easy self-rating of generalized anxiety disorder: validity of the Dutch web-based GAD-7, GAD-2 and GAD-SI. Psychiatry Research, 188, 58–64.
Foa, E. B., Huppert, J. D., Leiberg, S., Langner, R., Kichic, R., Hajcak, G., & Salkovskis, P. M. (2002). The obsessive-compulsive inventory: development and validation of a short version. Psychological Assessment, 14, 485–496.
Grant, B. F., Goldstein, R. B., Chou, S. P., Huang, B., Stinson, F. S., Dawson, D. A., & Compton, W. M. (2009). Sociodemographic and psychopathologic predictors of first incidence of DSM-IV substance use, mood and anxiety disorders: results from the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions. Molecular Psychiatry, 14, 1051–1066.
Greenberg, P. E., Sisitsky, T., Kessler, R. C., Finkelstein, S. N., Berndt, E. R., Davidson, J. R. T., & Fyer, A. J. (1999). The economic burden of anxiety disorders in the 1990s. Journal of Clinical Psychiatry, 60, 427–435.
Hoffman, D. L., Dukes, E. M., & Wittchen, H.-U. (2006). Human and economic burden of generalized anxiety disorder. Depression and Anxiety, 25, 72–90.
Hu, L., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: conventional criteria versus new alternatives. Structural Equation Modeling, 6, 1–55.
Kertz, S., Bigda‐Peyton, J., & Björgvinsson, T. (2013). Validity of the Generalized Anxiety Disorder‐7 Scale in an acute psychiatric sample. Clinical Psychology and Psychotherapy, 20, 456–464.
Kroenke, K., Spitzer, R. L., Williams, J. B., Monahan, P. O., & Löwe, B. (2007). Anxiety disorders in primary care: prevalence, impairment, comorbidity, and detection. Annals of Internal Medicine, 146, 317–325.
Lovibond, P. F., & Lovibond, S. H. (1995). The structure of negative emotional states: comparison of the Depression Anxiety Stress Scales (DASS) with the Beck Depression and Anxiety Inventories. Behaviour Research and Therapy, 33, 335–343.
Löwe, B., Decker, O., Müller, S., Brähler, E., Schellberg, D., Herzog, W., & Herzberg, P. Y. (2008). Validation and standardization of the Generalized Anxiety Disorder Screener (GAD-7) in the general population. Medical Care, 46, 266–274.
Meyer, T. J., Miller, M. L., Metzger, R. L., & Borkovec, T. D. (1990). Development and validation of the Penn State Worry Questionnaire. Behaviour Research and Therapy, 28, 487–495.
Mills, S. D., Fox, R. S., Malcarne, V. L., Roesch, S. C., Champagne, B. R., & Sadler, G. R. (2014). The psychometric properties of the Generalized Anxiety Disorder-7 Scale in Hispanic Americans with English or Spanish language preference. Cultural Diversity and Ethnic Minority Psychology, 20, 463–468.
Muthén, L. K., & Muthén, B. O. (2008–2014). Mplus 6.0 [Computer software]. Los Angeles: Author.
National Comorbidity Survey (NCS) (2011). NCS-R lifetime prevalence estimates. Available from: http://www.hcp.med.harvard.edu/ncs/ftpdir/NCS-R_Lifetime_Prevalence_Estimates.pdf. Accessed 22 August 2015
Raykov, T. (2001). Estimation of congeneric scale reliability via covariance structure models with nonlinear constraints. British Journal of Mathematical and Statistical Psychology, 54, 315–323.
Raykov, T. (2004). Behavioral scale reliability and measurement invariance evaluation using latent variable modeling. Behavior Therapy, 35, 299–331.
Roy-Byrne, P. P. (1996). Generalized anxiety and mixed anxiety-depression: association with disability and health care utilization. Journal of Clinical Psychiatry, 57, 86–91.
Roy-Byrne, P. P., & Katon, W. (1997). Generalized anxiety disorder in primary care: the precursor/modifier pathway to increased health care utilization. Journal of Clinical Psychiatry, 58, 34–40.
Ruiz, M. A., Zamorano, E., García-Campayo, J., Pardo, A., Freire, O., & Rejas, J. (2011). Validity of the GAD-7 scale as an outcome measure of disability in patients with generalized anxiety disorders in primary care. Journal of Affective Disorders, 128, 277–286.
Sousa, T. V., Viveiros, A., Chai, M. V., Vicente, F. L., Jesus, G., Carnot, M. J., & Ferreira, P. L. (2015). Reliability and validity of the Portuguese version of the Generalized Anxiety Disorder (GAD-7) scale. Health and Quality of Life Outcomes, 13, 1–8.
Spitzer, R. L., Kroenke, K., Williams, Williams, J. B. W., & Löwe, B. (2006). A brief measure for assessing generalized anxiety disorder. Archives of Internal Medicine, 166, 1092–1097.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Funding
This study was funded by the National Institute of Mental Health (Grant MH039096) to the second author. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Mental Health or the National Institutes of Health.
Conflict of Interest
Lauren A. Rutter declares that she has no conflict of interest. Timothy A. Brown declares that he has no conflict of interest.
Experiment Participants
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Ethical Approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed Consent
Informed consent was obtained from all individual participants included in the study.
Rights and permissions
About this article
Cite this article
Rutter, L.A., Brown, T.A. Psychometric Properties of the Generalized Anxiety Disorder Scale-7 (GAD-7) in Outpatients with Anxiety and Mood Disorders. J Psychopathol Behav Assess 39, 140–146 (2017). https://doi.org/10.1007/s10862-016-9571-9
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10862-016-9571-9