Age at First Attention-Deficit/Hyperactivity Disorder Diagnosis and Educational Outcomes

Early diagnosis of attention-deficit/hyperactivity disorder (ADHD) is often recommended, but it is unknown whether age at diagnosis is associated with educational outcomes.

To estimate whether age at ADHD diagnosis is associated with school performance, completed degrees, educational enrollment, and school dropout.

This population-based cohort study used national registry data for individuals born in Finland between January 1, 1990, and December 31, 1999, followed up until age 20 years. Individuals were born without a diagnosis of intellectual disability (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] codes F70-F79). Analyses were conducted from May 2024 to December 2025.

Age at ADHD diagnosis, identified by the first clinical diagnosis (International Classification of Diseases, Ninth Revision code 314; ICD-10 code F90; or medication purchase).

Grade point average (GPA; range, 4 [failing] to 10 [excellent]) at the end of compulsory education (approximately 16 years of age), completed degrees in upper secondary education (vocational or academic), enrollment in tertiary education, and school dropout at age 20 years.

The study sample included 580 132 individuals (51.2% male). Of these, 12 208 males (2.1%) and 3753 females (0.7%) had a first ADHD diagnosis between ages 4 and 20 years: mean (SD) age for males was 11.3 (4.1) years and for females was 14.4 (4.6) years. ADHD diagnosis at any age was associated with worse educational outcomes and greater likelihood of vocational than academic upper secondary education. After adjusting for sociodemographic covariates, if a diagnosis was received by age 16 years, younger age was associated with higher GPA for males (range, 7.12 [95% CI, 6.99-7.26] at age 4 years to 6.52 [95% CI, 6.46-6.58] at age 16 years) and females (range, 7.64 [95% CI, 7.49-7.78] at age 6 years to 6.95 [95% CI, 6.82-7.07]) at age 12 years, higher probability of completing an academic upper secondary degree for males (range, 20.77% [95% CI, 15.41%-26.12%] at age 4 years to 5.29% [3.78%-6.80%] at age 15 years) and females (range, 31.04% [95% CI, 15.60%-46.47%] at age 4 years to 12.01% [95% CI, 7.80%-16.21%] at age 14 years), and lower probability of school dropout for males (range, 9.16% [95% CI, 4.89%-13.42%] at age 4 years to 29.52% [95% CI, 25.85%-33.19%] at age 16 years) and females (range, 9.57% [95% CI, 4.49%-14.65%] at age 6 years to 27.16% [95% CI, 19.75%-34.57%] at age 13 years). However, after educational track choices (ages 17-20 years), older age at diagnosis was associated with higher and more academic education.

In this cohort study, earlier age at ADHD diagnosis was associated with better school performance, more academic education, and lower school dropout rates than diagnoses closer to age 16 years. The findings suggest that individuals who are diagnosed closer to age 16 years could benefit from targeted support to prevent school dropout.