Heterogeneity in educational outcomes following ADHD: a full population register-study in Finland

Abstract Background Prior evidence has linked attention-deficit/hyperactivity disorder (ADHD) to impaired educational success, but how this might depend on family, school, and area level characteristics remains unclear. To understand heterogeneity in the educational consequences of ADHD, we investigate moderating factors at different levels of the social environment. Methods Using total population register data, we identified all children born in Finland in 1998-2000 and diagnosed with ADHD at age 6-16 (n = 4,206, identified from data on healthcare visits and medication purchases), matched with non-diagnosed controls (n = 42,060). Causal forests were used to estimate average effects of ADHD on grade point average (GPA; scale 4-10, fail-excellent) at the end of compulsory education (∼age 16), and to identify key individual, family, school, and area level modifiers. Results Children with ADHD have 0.70 (95% CI 0.68-0.73) lower GPA than non-diagnosed children, but there is substantial variation in effect size. The most important modifiers are family level variables, particularly parental education, and gender. While girls and children from socioeconomically advantaged families have higher GPA and lower probability of ADHD than others, the negative association between ADHD and GPA appears strongest among them. Of school and area level factors, living in North Karelia, the region with highest ADHD prevalence, seems to matter most, with smaller differences in GPA between diagnosed and non-diagnosed children. Conclusions ADHD is associated with weaker educational success, and more so in population subgroups with lower rates of ADHD. While girls and children from socially advantaged backgrounds are less likely to have ADHD, their educational success is disproportionately affected by it. The weaker association in North Karelia may be linked to differences in healthcare practices, with children receiving diagnosis with milder symptoms that have less effect on educational outcomes. Key messages • Although ADHD is associated with weaker educational success, there is substantial heterogeneity in this association. • Girls and children from socioeconomically advantaged backgrounds have lower probability to be diagnosed with ADHD, but their educational success seems the most affected by it.