Testing the Discriminant and Convergent Validity of the World Health Organization Six-Item Adult ADHD Self-Report Scale Screener Using the Stockholm Public Health Cohort

Abstract

Objective: The World Health Organization (WHO) Adult ADHD Self-Report Scale (ASRS) is intended to measure population prevalence of ADHD. The short version ASRS-6 has yet not been validated in a population setting. Our aim was to examine the validity of the ASRS-6 in a general population. Method: We used the Stockholm Public Health Cohort 2014. The convergent validity was assessed using item response theory (IRT). The discriminant validity was assessed by examining the correlation between the ASRS and known correlates. Results: The ASRS-6 was unidimensional albeit with hyperactivity and impulsivity items fitting less good. IRT analysis showed that the item difficulty ranged between easy to hard and that the four items on inattention had good or very good discriminatory ability. Correlates were all in the expected direction. Conclusion: The ASRS-6 has adequate validity in the general population but reflects the duality of ADHD having both inattention and hyperactivity/impulsivity as sufficient and non-necessary criteria.