A brief measure for assessing generalized anxiety disorder: the GAD-7.
BACKGROUND
Generalized anxiety disorder (GAD) is one of the most common mental disorders; however, there is no brief clinical measure for assessing GAD. The objective of this study was to develop a brief self-report scale to identify probable cases of GAD and evaluate its reliability and validity.


METHODS
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.


RESULTS
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.


CONCLUSIONS
The GAD-7 is a valid and efficient tool for screening for GAD and assessing its severity in clinical practice and research.
Spitzer
Robert L
RL
Biometrics Research Department, New York State Psychiatric Institute, New York, NY 10032, USA. RLS8@Columbia.edu
Kroenke
Kurt
K
Williams
Janet B W
JB
Löwe
Bernd
B
D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology