Psychometric properties of the Generalized Anxiety Disorder 7-item scale in youth: Screening in a primary care sample.

BACKGROUND

Anxiety disorders in youth are frequently underdiagnosed and untreated, partly due to a lack of screening in primary care. The Generalized Anxiety Disorder 7-item (GAD-7) scale is a brief self-report measure designed to screen for anxiety in primary care settings. However, little is known about the psychometrics of this scale with adolescents.

METHODS

Participants included 579 youth age 11 to 17 years who received screening for depression in a primary care setting through a web-based application, VitalSign6, over a 4-year period. Psychometric analyses were completed based on classical test theory (CTT) and item response theory (IRT).

RESULTS

Using CTT and IRT methods, the GAD-7 has a unidimensional structure with good psychometric properties. In addition, the IRT analysis demonstrates that items 1 and 2 are strongly associated with the total score, and thus are good choices as a 2-item screening tool. Convergent validity was demonstrated, with high correlations between the GAD-7 and other measures of anxiety, and discriminant validity was also demonstrated, with low correlations to measures of other psychological states.

CONCLUSIONS

This psychometric evaluation of the GAD-7 provides support for the utility of this measure with adolescents. The GAD-2 is a good estimate of GAD-7 total score.