A landmark study in The Lancet Psychiatry has identified the dose thresholds beyond which ADHD medication stops adding benefit — and starts adding harm. Here are the questions parents should bring to the next appointment.

Common questions

What are the dose plateaus identified by the Lancet Psychiatry study?

For children and adolescents: methylphenidate around 45 mg/day, amphetamines around 25 mg/day, and guanfacine around 4 mg/day. For adults: amphetamines plateau above approximately 50 mg/day. Beyond these points, the 113-trial analysis found no evidence of additional mean group benefit, while side effects and medication discontinuations continued rising.

Does this mean my child should lower their medication dose?

Not automatically. The study identifies where the evidence for added benefit runs out. If your child is below the plateau and the medication is helping, the evidence supports staying in that range. If your child is above the plateau and experiencing side effects like sleep disruption or appetite suppression, this research gives you a science-backed basis to ask the prescriber whether a reduction is worth exploring. Never adjust a child’s medication without their prescriber’s guidance.

What should I ask at my child’s next medication appointment?

“A June 2026 study in The Lancet Psychiatry mapped dose-response plateaus for common ADHD medications. Where does my child’s current dose sit relative to those plateaus, and if we’re above them, is there evidence this dose level is still adding benefit?” That question opens a different conversation than “is the dose working” and grounds the answer in specific evidence.

If medication has limits, what else helps children who struggle with attention?

Attention challenges involve multiple processing systems — executive function, working memory, processing speed, and self-regulation — that medication does not directly train. Skill-building approaches that target these systems can improve how a child’s brain manages attention on its own. A screener is a useful starting point for identifying which systems need the most support, but it is not a diagnosis; for formal accommodations (IEP or 504 plan) or if you suspect a vision, hearing, or medical cause, a professional evaluation is the right route.