The factor structure and dimensional scoring of the generalized anxiety disorder questionnaire for DSM-IV.

Despite favorable psychometric properties, the Generalized Anxiety Disorder Questionnaire for the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (GAD-Q-IV) does not have a known factor structure, which calls into question use of its original weighted scoring system (usually referred to as the dimensional score). Analyses appropriate to categorical item responses in a large sample of undergraduates were used to establish the scale's factor structure. Analyses indicated that a one-factor structure resulted in good fit. A scoring method based on this one-factor structure was compared with a variety of alternative scoring procedures, and it was found that a method based on factor scores did relatively well but that the previously suggested dimensional score failed to perform better than a simple sum of items. Results support the general unity of the measure but raise doubts regarding its scoring and response options.