Psychometric properties of the DSM-5 Panic Disorder Dimensional Scale in an Australian community sample

Objective: The Panic Disorder Dimensional Scale (PD-D) was developed to provide a dimensional rating of panic disorder (PD) symptom severity alongside the traditional categorical Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnosis. The aim of the present study was to evaluate the psychometric properties of the PD-D in an Australian community sample. Method: Two-hundred and eighty-eight participants (72.9% female) aged 18-76 years (M = 28.28; SD = 12.08) completed the study. Results: Confirmatory factor analysis indicated that PD-D demonstrates a unidimensional factor (comparative fit index [CFI] = 0.95; Tucker-Lewis index (TLI) = 0.94; standardised root mean square residual [SRMR] = 0.04). The scale also demonstrated excellent internal consistency [alpha = .96 (95% CI: .95-.97); omega = 0.96 (95% CI: .95-.97)], and evidence of convergent and divergent validity. A good test-retest reliability was evident for the total PD-D score (ICC = .76, p < .001). Conclusions: The PD-D appears to be a reliable and valid measure which can be used to support diagnosis of PD in Australia. Limitations are discussed, including the use of a predominantly female sample and lack of clinician-informed data regarding current diagnoses.