Although generalized anxiety disorder (GAD) is one of the most common mental disorders, there is no brief clinical measure for assessing GAD. The objective of this study by US and German researchers was to develop a brief self-report scale to identify probable cases of GAD and evaluate its reliability and validity. A criterion-standard study was performed in 15 primary care clinics in the United States from November 2004 through June 2005. Of a total of 2740 adult patients completing a study questionnaire, 965 patients had a telephone interview with a mental health professional within 1 week. For criterion and construct validity, GAD self-report scale diagnoses were compared with independent diagnoses made by mental health professionals; functional status measures; disability days; and health care use.
The 7-item GAD asked patients:
How often during the past 2 weeks you had felt bothered by:
- feeling nervous, anxious, or on edge;
- not being able to stop or control worrying;
- worrying too much about different things;
- trouble relaxing;
- being so restless that it is hard to sit still;
- becoming easily annoyed or irritable; and
- feeling afraid as if something awful might happen?
They found: “A 7-item anxiety scale (GAD-7) had good reliability, as well as criterion, construct, factorial, and procedural validity. A cut point was identified that optimized sensitivity (89%) and specificity (82%). Increasing scores on the scale were strongly associated with multiple domains of functional impairment (all 6 Medical Outcomes Study Short-Form General Health Survey scales and disability days). Although GAD and depression symptoms frequently co-occurred, factor analysis confirmed them as distinct dimensions. Moreover, GAD and depression symptoms had differing but independent effects on functional impairment and disability. There was good agreement between self-report and interviewer-administered versions of the scale.”
The researchers concluded: “The GAD-7 is a valid and efficient tool for screening for GAD and assessing its severity in clinical practice and research."
The GAD-7 is a useful screening tool for identifying generalized anxiety disorder in primary care.
Arch Intern Med. 2006;166:1092-1097. May 22, 2006. © 2006 American Medical Association. All rights reserved.
A Brief Measure for Assessing Generalized Anxiety Disorder - The GAD-7, Robert L. Spitzer, MD; Kurt Kroenke, MD; Janet B. W. Williams, DSW; Bernd Löwe, MD, PhD
Category P. Psychological. Keywords: generalized anxiety disorder, diagnosis, screening, primary care, GAD-7, questionnaire, validation study
Synopsis edited by Professor Wes Fabb, Melbourne. Posted on Global Family Doctor 29 June 2006
