Generalized Anxiety Disorder Screener-7 (GAD-7)

The Generalized Anxiety Disorder Screener (GAD-7; Spitzer, Kroenke, Williams, & Lowe, 2006) is a brief, 7-item self-report measure for anxiety symptoms in adolescents (Daig, Herschbach, Lehmann, Knoll, & Decker, 2009; Farrand & Woodford, 2013; Johnson, Harris, Spitzer, & Williams, 2002) and adults (Spitzer et al., 2006). Although developed primarily as a screening tool for GAD, it can also be used as: a) a diagnostic tool (Spitzer et al., 2006), b) to monitor changes in symptoms over time (Kertz, Bigda-Peyton, & Bjorgvinsson, 2013), and as a screener for social anxiety, panic disorder, and post-traumatic stress disorder (Kroenke, Spitzer, Williams, Monahan, & Lowe, 2007).

The development of the GAD-7 began with the development the Primary Care Evaluation of Mental Disorders (PRIME-MD) at Columbia University, USA. The PRIME-MD was an instrument developed and validated in the early 1990s to diagnose five of the most common mental disorders presenting in clinical populations, including anxiety (Spitzer et al., 1994). It comprised a 2-stage process including self-report and clinically administered items for screen positive individuals. However, the length of time this process took (up to 12 minutes in clinical populations) proved a barrier to universal screening in primary practice, and was thus modified, developed, and validated into the Patient Health Questionnaire (PHQ; Spitzer, Kroenke, & Williams, 1999; Spitzer, Williams, Kroenke, Hornyak, & McMurray, 2000). The GAD-7 is one of the key questionnaires in the PHQ, and has been validated in 2740 primary care patients (Spitzer et al., 2006). Example items include “Feeling nervous, anxious or on edge”, “Not being able to stop or control worrying”, and “Worrying too much about different things”. Each item is rated on a likert-type scale from zero (“not at all”) to three (“nearly every day”), with total scores ranging from 0 to 21 (< 5 mild anxiety; 10-15 moderate anxiety; 15+ severe anxiety). Individuals with scores of 10+ are recommend for further assessment (Spitzer et al, 2006).

The GAD-7 demonstrates good convergent validity with the Beck Anxiety Inventory (r = 0.72) (BAI; Beck, Epstein, Brown, & Steer, 1988) and the anxiety subscale of the Symptom Checklist-90 (r = 0.74) (SCL-90; Derogatis, Lipman, Rickels, Uhlenhuth, & Covi, 1974). It also has excellent internal consistency (α = .92) and test-retest reliability (r = .83; Spitzer et al., 2006). A recent systematic review and diagnostic meta-analysis of 11 studies by Plummer, Manea, Trepel, and McMillan (2016) revealed the GAD-7 had acceptable properties for identifying GAD at cut off scores between 7-10, with optimal sensitivity/ specificity at a cut-off of 8 [sensitivity: 0.83 (95% CI 0.71–0.91), specificity: 0.84 (95% CI 0.70–0.92)].

The GAD-7 is available in over 20 languages, including English, Spanish, French, and Mandarin. Cultural adaptations of the Spanish (Garcia-Campayo et al., 2010) and Portuguese (Sousa et al., 2015) versions demonstrates good to excellent internal consistency, reliability, and validity (.71+). Criteria validity (using Receiver Operator Characteristic (ROC) curve analysis for the Spanish version also showed excellent specificity, sensitivity, positive, and negative predictive values (86%+) (Mills et al., 2014). The GAD-7, including manual, instructions and all translations, are available free online (http://www.phqscreeners.com), with no permissions required to reproduce, translate, display or distribute them.

Based on the available literature reviewed, it is recommended that the GAD-7 is useful both as a clinical instrument and in research; however, there is a caveat to be aware of – the PHQ (of which GAD-7 is part of), was developed with the support of an educational grant from Pfizer Inc, a pharmaceutical company, and it is not clear if the authors receive any royalties from Pfizer. However, it is beneficial to see good convergent validity with other well-known anxiety instruments, report in peer reviewed journals (including from teams not associated with the authors and Pfizer), and declaration of funding from Pfizer.

 

References

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Daig, I., Herschbach, P., Lehmann, A., Knoll, N., & Decker, O. (2009). Gender and age differences in domain-specific life satisfaction and the impact of depressive and anxiety symptoms: a general population survey from Germany. Quality of Life Research, 18(6), 669-678. doi:10.1007/s11136-009-9481-3

Derogatis, L. R., Lipman, R. S., Rickels, K., Uhlenhuth, E. H., & Covi, L. (1974). The Hopkins Symptom Checklist (HSCL): A self-report symptom inventory. Behavioral Science, 19(1), 1-15. doi:10.1002/bs.3830190102

Farrand, P., & Woodford, J. (2013). Measurement of individualised quality of life amongst young people with indicated personality disorder during emerging adulthood using the SEIQoL-DW. Quality of Life Research, 22(4), 829-838. doi:10.1007/s11136-012-0210-y

Garcia-Campayo, J., Zamorano, E., Ruiz, M. A., Pardo, A., Perez-Paramo, M., Lopez-Gomez, V., . . . Rejas, J. (2010). Cultural adaptation into Spanish of the generalized anxiety disorder-7 (GAD-7) scale as a screening tool. Health and Quality of Life Outcomes, 8, 8. doi:10.1186/1477-7525-8-8

Johnson, J. G., Harris, E. S., Spitzer, R. L., & Williams, J. B. (2002). The patient health questionnaire for adolescents: validation of an instrument for the assessment of mental disorders among adolescent primary care patients. Journal of Adolescent Health, 30(3), 196-204.

Kertz, S., Bigda-Peyton, J., & Bjorgvinsson, T. (2013). Validity of the Generalized Anxiety Disorder-7 scale in an acute psychiatric sample. Clin Psychol Psychother, 20(5), 456-464. doi:10.1002/cpp.1802

Kroenke, K., Spitzer, R. L., Williams, J. B., Monahan, P. O., & Lowe, B. (2007). Anxiety disorders in primary care: prevalence, impairment, comorbidity, and detection. Annals of Internal Medicine, 146(5), 317-325.

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(3), 463-468. doi:10.1037/a0036523

Plummer, F., Manea, L., Trepel, D., & McMillan, D. (2016). Screening for anxiety disorders with the GAD-7 and GAD-2: a systematic review and diagnostic metaanalysis. General Hospital Psychiatry, 39, 24-31. doi:10.1016/j.genhosppsych.2015.11.005

Sousa, T. V., Viveiros, V., 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), 50. doi:10.1186/s12955-015-0244-2

Spitzer, R. L., Kroenke, K., & Williams, J. B. (1999). Validation and utility of a self-report version of PRIME-MD: the PHQ primary care study. Primary Care Evaluation of Mental Disorders. Patient Health Questionnaire. JAMA, 282(18), 1737-1744.

Spitzer, R. L., Kroenke, K., Williams, J. B., & Lowe, B. (2006). A brief measure for assessing generalized anxiety disorder: the GAD-7. Archives of Internal Medicine, 166(10), 1092-1097. doi:10.1001/archinte.166.10.1092

Spitzer, R. L., Williams, J. B., Kroenke, K., Hornyak, R., & McMurray, J. (2000). Validity and utility of the PRIME-MD patient health questionnaire in assessment of 3000 obstetric-gynecologic patients: the PRIME-MD Patient Health Questionnaire Obstetrics-Gynecology Study. American Journal of Obstetrics and Gynecology, 183(3), 759-769.

Spitzer, R. L., Williams, J. B., Kroenke, K., Linzer, M., deGruy, F. V., 3rd, Hahn, S. R., . . .Johnson, J. G. (1994). Utility of a new procedure for diagnosing mental disorders in primary care. The PRIME-MD 1000 study. JAMA, 272(22), 1749-1756.