Investigating the validity of the Strengths and Difficulties Questionnaire to assess ADHD in young adulthood

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) symptoms typically onset early in development and persist into adulthood for many. Robust investigation of symptom continuity and discontinuity requires repeated assessments using the same measure, but research is lacking into whether measures used to assess ADHD symptoms in childhood are also valid in adulthood. The Strengths and Difficulties Questionnaire (SDQ) has been widely used to measure ADHD symptoms in children, but little is known about its utility to measure ADHD in adulthood. We used Receiver Operating Characteristic (ROC) curve analyses to examine the validity of the SDQ hyperactivity/ADHD subscale to distinguish between cases and non-cases of DSM-5 ADHD classified using the Barkley Adult ADHD Rating Scale-IV (BAARS-IV) at age 25 years in a UK population cohort (N=4121). Analyses suggested that the SDQ ADHD subscale had high accuracy in distinguishing ADHD cases from non-cases in young adulthood (area under the curve=0.90, 95% CI=0.87-0.93) and indicated a lower cut-point for identifying those who may have an ADHD diagnosis in this age group compared to that currently recommended for younger ages. Our findings suggest that the SDQ is suitable for ADHD research across different developmental periods, which will aid the robust investigation of ADHD from childhood to young adulthood.