Long-Term Effects of ADHD Medications in Children: A Retrospective Cohort Study of 100 Patients

Abstract

Background: Attention-deficit/hyperactivity disorder (ADHD) is commonly treated with stimulant (methylphenidate, amphetamines) and non-stimulant (atomoxetine, guanfacine) medications. Long-term safety data in children remain an active area of research, especially for growth, cardiovascular, and neuropsychiatric outcomes. Objective: To evaluate long-term (≥24 months) physical and neuropsychiatric effects associated with ADHD pharmacotherapy in children treated in a tertiary care clinic. Methods: Retrospective review of 100 consecutive children (6–16 years) diagnosed with ADHD and treated with medication for ≥24 months between 2018 and 2024. Outcomes included changes in height/weight z-scores, resting heart rate and blood pressure, incidence of new psychiatric diagnoses (depression, anxiety), and treatment-related adverse events. Basic statistical comparisons used paired t-tests and chi-square tests; significance set at p<0.05. Results:  Mean follow-up was 36.4 ± 9.2 months. Overall, stimulant-treated children (n=70) showed a small but statistically significant reduction in height velocity in the first 12 months (mean change −0.35 cm/year, p=0.02) with partial catch-up by 36 months (net −0.9 cm vs expected; p=0.08). Weight z-score decreased at 12 months (mean Δz −0.18, p=0.03) with partial recovery. Modest increases in mean resting heart rate (+6 bpm) and systolic BP (+4 mmHg) were observed in stimulant groups (p<0.05). No increase in major cardiovascular events was observed. Incidence of new depressive or anxiety disorders was not significantly higher in medicated children; in some subgroups, medication exposure correlated with reduced behavioral comorbidity. Conclusion: In this cohort, long-term ADHD pharmacotherapy was associated with modest, mostly reversible effects on growth and small increases in heart rate and blood pressure, but not with increased major cardiovascular or neuropsychiatric morbidity. Regular monitoring and individualized risk–benefit assessment remain essential.