The psychometric properties of 30-day versions of the DSM-5 dimensional severity scales for social anxiety disorder and panic disorder

Objectives: The current study aimed to investigate the psychometric properties of the DSM-5 dimensional severity scales for social anxiety disorder (SAD) and panic disorder (PD) using a past 30 day timeframe. Methods: Data were from a sample of 1,052 Australian community dwelling adults (aged 18 years or older) recruited using online advertisements. Respondents completed the DSM-5 severity scales for SAD and PD as well as a range of additional widely used self-administered scales for SAD and PD in the past 30 days prior to the survey. Results: Both scales exhibited high internal consistency (alpha>=0.94) and a strong general factor that justified unidimensional item response analysis (OmegaH=0.96). There was no evidence of significant local dependence amongst item pairs after accounting for the single factor. Similarly, there was no evidence for meaningful differential item functioning of the scales across sex, age, education level, and residential location. There was high convergent validity (0.71 - 0.85) amongst conceptually related scale and moderate to high correlations (0.54 - 0.80) between conceptually unrelated scales. Conclusions: These findings provide support for the use of past month versions of the DSM-5 severity scales for SAD and PD by researchers and clinicians to inform and supplement diagnostic decisions.