Psychometric properties of the Generalised Anxiety Disorder Dimensional Scale in an Australian sample

Abstract

The Generalised Anxiety Disorder Dimensional Scale is a new measure of generalised anxiety disorder developed to assist clinicians in the dimensional assessment of generalised anxiety disorder by the Diagnostic and Statistical Manual (Fifth Edition) Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic, and Dissociative Disorder Work Group. This study aims to evaluate the psychometric properties of the scale in an Australian community sample. A sample of 293 Australians (72.7% female) aged between 18 and 73 (M = 28.31 years; SD = 12.11 years) was recruited. Participants completed the Generalised Anxiety Disorder Dimensional Scale, as well as related measures used to assess convergent and discriminant validity. A small proportion of the sample (n = 21) completed the scale a second time to assess test-retest reliability. The scale demonstrated a unidimensional factor structure, good internal consistency (Cronbach’s α = .94), good test-retest reliability (ICC = .85), good convergent validity with the Generalised Anxiety Disorder– 7 item (rs = .77), and discriminant validity with the Panic Disorder Severity Scale–Self Report (rs = .63). The scale appears to be a reliable and valid measure of generalised anxiety disorder symptomology for use in the Australian population.