Associations between academic achievement and ADHD in Sweden 2001-2018: differential trends for native and immigrant...

There is a strong achievement-gradient in attention-deficit hyperactivity disorder (ADHD), with a higher prevalence in children with low academic achievement. In Sweden, the prevalence of ADHD is also higher among native than immigrant children. The aim of this study was to investigate whether the change in diagnosed ADHD varies across different achievement levels, and whether this change in turn differs depending on students' immigration status.

Register data on all students graduating from compulsory school in Sweden between 2001 and 2018 were used. ADHD was measured by diagnosis in specialised care recorded in the year of graduation, and academic achievement by students' grade point average. Logistic regression models with ADHD as the outcome were used. Changes in the association between achievement and ADHD over time were tested by including interactions terms for achievement and year.

There was a positive interaction between achievement and year in the pooled sample, meaning that ADHD increased relatively more among higher-achieving students and that the achievement-gradient in ADHD diminished over time. In stratified analyses, the greatest relative increase in ADHD was observed among higher-achieving native and second-generation immigrant students, and the smallest among low-achieving first-generation immigrants. The achievement-gradient was flatter, and diminished more, among immigrant students.

The reduced achievement-gradient in ADHD suggests that the absence of academic difficulties to a lesser degree disqualifies children from diagnosis. The limited increase among low-achieving first-generation immigrants may indicate persistent barriers to diagnosis and care in this group.