Scientific background: Anxiety

About this test

The GAD-7 was developed by Spitzer, Kroenke, Williams, and Löwe (2006) and is — alongside the PHQ-9 — one of the most extensively studied and widely used screening instruments in clinical psychology. Studies show good internal consistency (Cronbach's alpha usually above .89) and good sensitivity and specificity, not only for generalized anxiety disorder but also as a general indicator for panic disorder, social phobia, and PTSD. The GAD-7 is a screening and monitoring tool, not a diagnosis by itself.

In the original validation study on a large primary care sample, a cutoff of 10 points gave the best balance of sensitivity (89%) and specificity (82%). Importantly, these figures don't automatically transfer to every population: a later study in a psychiatric sample (people already in treatment for another mental health condition) found notably weaker discrimination at the same cutoff (sensitivity 74%, specificity 54%) -- a reminder that screening accuracy depends on the population being tested, not just the questionnaire itself.

Dimensions

Sources & license

• Spitzer, R. L., Kroenke, K., Williams, J. B. W., & Löwe, B. (2006). A brief measure for assessing generalized anxiety disorder: The GAD-7. Archives of Internal Medicine, 166(10), 1092–1097.

  The GAD-7 is in the public domain and may be reproduced, translated, and used without permission.

  https://www.phqscreeners.com

• Johnson, S. U., Ulvenes, P. G., Øktedalen, T., & Hoffart, A. (2019). Psychometric properties of the General Anxiety Disorder 7-Item (GAD-7) Scale in a heterogeneous psychiatric sample. Frontiers in Psychology, 10, 1713.

  Scientific publication, cited as evidence for population-dependent diagnostic accuracy.