Assessing the Construct Validity of the Adult ADHD Self-report Scale for DSM-5 and Prevalence of ADHD in a Danish Population Sample

Objective: This study examines the validity of the ASRS-5 as a new screening tool for ADHD and evaluates its proposed screening cut-off in a general population context. Method: A nationally representative sample of 2,002 individuals aged 18 to 80 years was surveyed using the ASRS-5, with complete data obtained from 714 participants. Psychometric analysis evaluated fit to the Rasch model, response categories, dimensionality, differential item functioning, local dependency, and reliability. A cut-off score of 14, based on a simple additive scale, was applied. Results: The ASRS-5 generally conformed to the expectations of the Rasch model. However, disordered response categories were observed for item 6, and gender-related differential item functioning was noted in items 3, 4, and 6. The ASRS-5 demonstrated a unidimensional construct, and a cut-off score of 14 identified 6.0% of the sample as potential ADHD cases. Conclusion: Although the ASRS-5 aligns well with the Rasch model, certain measurement challenges exist. The recommended cut-off score effectively identifies an ADHD prevalence consistent with the 6.5% reported in the original ASRS-5 study.