Sleep and Stroop Performance with Adjunctive Melatonin in Pharmacotherapy-stable Pediatric ADHD: A Prospective Open-label Study

Background: Attention-deficit/hyperactivity disorder (ADHD) is frequently comorbid with sleep disturbances; evidence linking melatonin to objective neurocognitive outcomes in this population is lacking. The present study assessed the association of melatonin with parent-reported sleep disturbance scores and Stroop Color–Word Test performance in children and adolescents with ADHD and comorbid sleep disturbances on stable pharmacotherapy. Methods: Prospective, open-label, single-arm, 6-week study. Thirty-three participants (ADHD; Children’s Sleep Habits Questionnaire [CSHQ] score ≥41) on stable methylphenidate or atomoxetine were enrolled; 32 completed follow-up. Melatonin (3 mg/day <40 kg; 5 mg/day ≥40 kg) was administered 1 hour before bedtime. Primary outcome: CSHQ total score (baseline, weeks 2, 4, 6). Secondary outcome: Psychology Experiment Building Language Stroop Color–Word Test (baseline and week 6). Analysis involved repeated-measures analysis of variance and paired t tests. Results: Total CSHQ scores declined from 50.25 ± 3.60 to 34.31 ± 2.69 at 6 weeks ( F =506.238, p < .001, partial η ²=0.942), with significant improvement in six of eight subscales after Bonferroni correction. Pre- and post-Stroop scores showed large observed changes ( d =1.12–1.19; all p < .001), though practice effects cannot be excluded without a control group. Sleep–cognition correlations were small and non-significant ( r =0.19–0.29; p > .10). Adverse effects were mild and transient. Conclusions: Pre- and post-improvements in parent-reported sleep scores and Stroop performance were observed over 6 weeks of melatonin use; given the single-arm design, causal attribution is not possible. Randomized controlled trials with objective sleep measures and parallel cognitive assessment forms are warranted.