Philosophy

Statistics

Psychiatry

Measurement invariance

Anxiety

Psychometrics

Patient Health Questionnaire

Structural equation modeling

Environmental health

Confirmatory factor analysis

Construct validity

Psychology

Mathematics

Generalized anxiety disorder

Normative

Epistemology

Population

Medicine

Depressive symptoms

Clinical psychology

Medical Care

The 7-item Generalized Anxiety Disorder Scale (GAD-7) is a practical self-report anxiety questionnaire that proved valid in primary care. However, the GAD-7 was not yet validated in the general population and thus far, normative data are not available.To investigate reliability, construct validity, and factorial validity of the GAD-7 in the general population and to generate normative data.Nationally representative face-to-face household survey conducted in Germany between May 5 and June 8, 2006.Five thousand thirty subjects (53.6% female) with a mean age (SD) of 48.4 (18.0) years.The survey questionnaire included the GAD-7, the 2-item depression module from the Patient Health Questionnaire (PHQ-2), the Rosenberg Self-Esteem Scale, and demographic characteristics.Confirmatory factor analyses substantiated the 1-dimensional structure of the GAD-7 and its factorial invariance for gender and age. Internal consistency was identical across all subgroups (alpha = 0.89). Intercorrelations with the PHQ-2 and the Rosenberg Self-Esteem Scale were r = 0.64 (P < 0.001) and r = -0.43 (P < 0.001), respectively. As expected, women had significantly higher mean (SD) GAD-7 anxiety scores compared with men [3.2 (3.5) vs. 2.7 (3.2); P < 0.001]. Normative data for the GAD-7 were generated for both genders and different age levels. Approximately 5% of subjects had GAD-7 scores of 10 or greater, and 1% had GAD-7 scores of 15 or greater.Evidence supports reliability and validity of the GAD-7 as a measure of anxiety in the general population. The normative data provided in this study can be used to compare a subject's GAD-7 score with those determined from a general population reference group.

Validation and Standardization of the Generalized Anxiety Disorder Screener (GAD-7) in the General Population