Methylphenidate Is Safe Over Two Years

Reassurance about growth problems, but cardiovascular monitoring still matters

STUDY: Man KKC et al, Lancet Psychiatry 2023;10:323–333

STUDY TYPE: Prospective cohort study

FUNDING: EU Seventh Framework Programme

Background

It’s difficult to run long-term, controlled trials on medications, which is why we have so few with methylphenidate. This, which lasted two years, is a significant advance.

The Study

• 1,410 stimulant-naive children and adolescents aged 6–17 with ADHD in Europe
• Comparing 756 who started methylphenidate against 391 who did not, with assessments over 24 months.
• Outcomes included growth, cardiovascular parameters, and psychiatric and neurological safety measures (tics, psychosis-like symptoms, suicidality, mood, and substance use).

Methylphenidate did not affect height velocity at any time point. Weight gain slowed briefly at 6 months but normalized by 12 months. No differences emerged in rates of psychosis-like symptoms, suicidality, tics, or substance use between groups.

Mood improved more in the methylphenidate group. Heart rate, systolic blood pressure, and diastolic blood pressure were modestly but consistently higher in the medicated group throughout follow-up.

Limitations

Dropout rates (only 52% completed the full two years for data collection). The study was not randomized, but the two control groups were reasonably well matched for comparison. The average age was 9, so the critical 12–15 year growth window identified by the Multimodal Treatment of ADHD Study wasn’t well covered.

Practice Implications

1. No meaningful growth suppression.
2. No increase in psychiatric or neurological risks.
3. A small but real cardiovascular risk.
4. Learn more about the risks of tolerance with stimulants.