The impact of ADHD and neurostimulant treatment on normalized height deviance after accounting for genetic height potential

Abstract Background Studies have reported conflicting findings regarding whether attention-deficit/hyperactivity disorder (ADHD) and neurostimulant (NS) treatment influence growth. The study aimed to evaluate the impact of ADHD and NS-treatment on adult height (AH), while accounting for individual expected height. Methods Retrospective controlled cohort study using a nationwide healthcare provider database. Children born 1995-2003 were classified into: (1) untreated ADHD, (2) NS-treated ADHD, and (3) controls, followed until AH (girls ≥17 years, boys ≥19 years). Observed height index (OHI) = individual AH ÷ sex-specific mean AH of controls. Expected height index (EHI) = individual’s MPH ÷ sex-specific mean MPH of controls. Normalized height deviance (NHD) = OHI − EHI. ADHD impact = mean NHD(untreated ADHD) − mean NHD(controls). NS-treatment impact = mean NHD(NS-treated) − mean NHD(untreated ADHD). Significance was set at p ≤ 0.05. Effect sizes reported as Cohen’s d and f . Results The cohort included 17,517 children with ADHD (5671 untreated; 11,846 NS-treated) and 47,258 controls. Girls’ ADHD impact was −0.28% ( p < 0.001; Cohen’s d = 0.08), and in boys −0.11% ( p = 0.12; Cohen’s d = 0.03). Girls’ NS-treatment impact was −0.26% ( p = 0.005, Cohen’s d = 0.07), in boys −0.10% ( p = 0.25). Conclusions ADHD and NS-treatment were associated with negligible effect sizes in girls and non-significant differences in boys. Impact After accounting for individual familial genetic height potential, ADHD and neurostimulant treatment are associated with statistically detectable but clinically negligible differences in adult height. Introduces normalized height deviance (NHD), a genetics-adjusted measure that distinguishes true growth effects from delayed maturation. Uses a large, nationwide cohort followed to adult height, resolving long-standing inconsistencies in prior growth studies. Provides reassurance that ADHD and neurostimulant treatment do not meaningfully impair final adult stature and supports informed clinical decision-making.