Does ADHD medication affect growth?

Your child has lost their appetite, the growth chart is the only thing anybody at the clinic looks at, and somebody online has told you stimulants cost four centimetres of adult height. That number is real, it comes from a good study, and it describes a group of fifty-three people who chose to stay on medication for sixteen years — which is not the same thing as what happens to your child.

The short answer: yes, modestly, and the honest figures are smaller than the ones that circulate. In the longest follow-up, adults who had ADHD as children were 1.29 centimetres shorter than a local comparison group — an effect size of 0.21. Within that cohort, a self-selected group of fifty-three people who took stimulants consistently across sixteen years ended up about 2.5 to 4 centimetres shorter than those who took them negligibly. The paediatric guideline summarises the whole-cohort effect as "in the range of 1 to 2 cm from predicted adult height." All of these comparisons are between groups who chose their own treatment, not between randomised arms, so they cannot separate the drug from the reasons people stay on it. What follows is what is actually known and what to monitor.¹ ² ³

The figures, with their provenance

The subgroups matter. Of 568 people followed, 53 (9 percent) were in the consistent-use group, 374 (66 percent) inconsistent, and 141 (25 percent) negligible.² Those groups formed themselves; nobody was randomised to sixteen years of medication.

The authors' own conclusion from the young-adult paper is worth quoting whole, because it contains both halves: "Within naturalistic subgroups of ADHD cases, extended use of medication was associated with suppression of adult height but not with reduction of symptom severity."¹

That second clause is the uncomfortable one, and it belongs in the conversation. In these self-selected subgroups, staying on medication for sixteen years was associated with a height difference and not with better symptoms. It is observational — the people who stay on medication for sixteen years are likely the ones who need it most — but it is a reason to keep asking whether treatment is still doing something, not only whether it is safe.

Weight goes the other way in the long run. Weight z-scores diverged early among the subgroups, converged in adolescence, then diverged again in adulthood, with the consistent-use group heavier than the comparison group by the end.² Appetite suppression in childhood does not translate into a thinner adult.

What happens in the shorter run

Growth suppression appears early and is measurable. In the naturalistic follow-up of the landmark trial, the authors described "continued mild growth suppression" among children who consistently used stimulants over two years, alongside maintained symptom benefit.⁴

And the regulator has recently sharpened its language for the youngest children: in 2025 the FDA required expanded labelling stating that "Clinically significant weight loss (at least 10% decrease in the CDC weight percentile) was observed in both short- and long-term studies with extended-release stimulants" in children under six, that those children "have higher plasma exposures… and higher rates of side effects than older children," and that "the benefits of extended-release stimulants may not outweigh the risks of these products in patients younger than 6 years with ADHD."⁵

That is a specific, age-banded warning. It is not a statement about eight-year-olds.

What to actually do

Monitoring is the answer, and it is cheap.

• Height and weight at every medication review, plotted on a chart rather than noted in a chart. A number in isolation tells you nothing; a trajectory tells you everything.
• Know your child's own percentile line before starting, so you have a baseline to compare against.
• Watch appetite as the mechanism. Weight loss precedes height effects, and appetite is where the intervention is. Practical adjustments — a substantial breakfast before the dose takes hold, a real evening meal after it wears off, calorie-dense snacks — are standard and worth asking about specifically.
• Ask about timing and formulation. Different preparations cover different parts of the day, and a child whose appetite returns at 4 p.m. is a different problem from one whose does not return at all.
• Ask about planned breaks. Some families and clinicians use holidays or weekends off medication; the evidence on whether this restores growth is not strong enough to promise anything, but it is a reasonable thing to discuss and a common practice.
• Titrate rather than escalate. The guideline instruction is to titrate "to achieve maximum benefit with tolerable side effects" — appetite loss severe enough to move a growth curve is a tolerability problem, and tolerability problems are a reason to adjust.³
• Bring it up early. The families who end up with the largest effects are usually the ones where nobody weighed the child for two years.

How to weigh this against everything else

Three things belong on the other side of the scale, and a parent is entitled to all of them.

The effect is small at the group level. An effect size of 0.21 between children with ADHD and their classmates, and a guideline summary of one to two centimetres.¹ ³

The comparisons are not randomised. They compare people who chose to keep taking medication with people who chose not to, and those groups differ in severity, family circumstances and much else. This is the same design limitation that appears throughout the long-term ADHD literature, and it cuts both ways.

Untreated ADHD is not neutral. Large within-individual studies find substantially lower rates of motor vehicle crashes, criminal convictions and all-cause mortality during medicated periods than during unmedicated ones in the same people.⁶ ⁷ ⁸ Those are also observational — but they are the counterweight that a page listing only the risks would be hiding.

The decision this evidence supports is not "medicate or don't." It is: monitor growth deliberately, treat appetite loss as a clinical problem to be solved rather than a cost to be absorbed, and keep checking that the treatment is still earning its place. The full medication decision →

Q&A

Q: Do stimulants stunt growth? A: They are associated with a modest reduction in adult height. The whole-cohort figure in the longest follow-up is 1.29 ± 0.55 cm against a comparison group, with the paediatric guideline summarising it as one to two centimetres from predicted adult height.¹ ³

Q: Where does the "four centimetres" figure come from? A: From a comparison of two self-selected subgroups within that cohort — 53 people who took stimulants consistently across sixteen years against 141 who took them negligibly.² It is a real finding about a small, unrandomised group, not the expected effect for a typical child on medication.

Q: Is the lost height regained if we stop? A: The long follow-up measured adult height in people whose medication use varied over sixteen years, and found the differences persisted into adulthood in the consistent-use group.¹ ² What it cannot tell you is what happens for an individual child who stops at twelve, because that comparison was not made.

Q: My child has lost weight since starting. Is that expected? A: Appetite suppression is a recognised effect, and for children under six the FDA now requires labelling noting clinically significant weight loss in both short- and long-term studies.⁵ It is a reason to contact the prescriber, not a reason to wait until the next scheduled visit.

Q: Should we take medication holidays? A: Common practice, discussed case by case. The evidence that breaks restore growth is not strong enough for anyone to promise it, and the trade-off is the weeks without treatment. Worth raising as a question rather than doing unilaterally.

Q: Does non-stimulant medication avoid this? A: The growth evidence above is about stimulants specifically. Non-stimulant options have their own effect and tolerability profiles — in the network meta-analysis atomoxetine was less effective than the stimulants but is a real alternative.⁹ A prescriber can weigh which trade-off fits your child.

Ready to find a clinician who will monitor this properly? Filter by approach, schedule and payment route → · ADHD in children: the parent map → · The printable evaluation prep →

Sources

1. Swanson JM, Arnold LE, Molina BSG, et al., "Young adult outcomes in the follow-up of the multimodal treatment study of attention-deficit/hyperactivity disorder: symptom persistence, source discrepancy, and height suppression," Journal of Child Psychology and Psychiatry 58(6), 2017, 663–678 — "For adult height, the ADHD group was 1.29 ± 0.55 cm shorter than the LNCG (p < .01, d = .21)… the treated group with the Consistent or Inconsistent pattern was 2.55 ± 0.73 cm shorter than the subgroup with the Negligible pattern (p < .0005, d = .42), and within the treated group, the subgroup with the Consistent pattern was 2.36 ± 1.13 cm shorter than the subgroup with the Inconsistent pattern (p < .04, d = .38)"; "extended use of medication was associated with suppression of adult height but not with reduction of symptom severity" — doi.org.
2. Greenhill LL, Swanson JM, Hechtman L, et al., "Trajectories of growth associated with long-term stimulant medication in the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder," Journal of the American Academy of Child and Adolescent Psychiatry 59(8), 2020, 978–989 — the self-selected subgroups of 53 (9%), 374 (66%) and 141 (25%); "Consistent was shorter than Negligible (-0.66 z units / -4.06 cm / 1.6 inches, t = -3.17, p < 0.0016)"; the weight trajectory diverging again in adulthood — doi.org.
3. Wolraich ML, Hagan JF Jr, Allan C, et al., "Clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents," Pediatrics 144(4), 2019, e20192528 — the guideline's summary of the MTA growth findings as "in the range of 1 to 2 cm from predicted adult height," and key action statement 6 on titrating "to achieve maximum benefit with tolerable side effects" — pmc.ncbi.nlm.nih.gov.
4. MTA Cooperative Group, "National Institute of Mental Health Multimodal Treatment Study of ADHD follow-up: changes in effectiveness and growth after the end of treatment," Pediatrics 113(4), 2004, 762–769 — "exploratory naturalistic analyses suggest that consistent use of stimulant medication was associated with maintenance of effectiveness but continued mild growth suppression" — doi.org.
5. US Food and Drug Administration, "FDA requires expanded labeling about weight loss risk in patients younger than 6 years taking extended-release stimulants," drug safety communication, 30 June 2025 — "Clinically significant weight loss (at least 10% decrease in the CDC weight percentile) was observed in both short- and long-term studies with extended-release stimulants"; "patients younger than 6 years have higher plasma exposures … and higher rates of side effects than older children"; "the benefits of extended-release stimulants may not outweigh the risks of these products in patients younger than 6 years with ADHD" — fda.gov.
6. Chang Z, Quinn PD, Hur K, et al., "Association between medication use for attention-deficit/hyperactivity disorder and risk of motor vehicle crashes," JAMA Psychiatry 74(6), 2017, 597–603 — 2,319,450 patients; 38% and 42% lower crash risk during medicated months in males and females — pmc.ncbi.nlm.nih.gov.
7. Lichtenstein P, Halldner L, Zetterqvist J, et al., "Medication for attention deficit-hyperactivity disorder and criminality," New England Journal of Medicine 367(21), 2012, 2006–2014 — 32% and 41% reductions in criminality rate during medicated periods — pmc.ncbi.nlm.nih.gov.
8. Li L, Zhu N, Zhang L, et al., "ADHD pharmacotherapy and mortality in individuals with ADHD," JAMA 331(10), 2024, 850–860 — all-cause mortality hazard ratio 0.79 (95% CI 0.70 to 0.88) after medication initiation — pmc.ncbi.nlm.nih.gov.
9. Cortese S, Adamo N, Del Giovane C, et al., "Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults," The Lancet Psychiatry 5(9), 2018, 727–738 — atomoxetine SMD −0.56 against placebo on clinician ratings in children and adolescents — pmc.ncbi.nlm.nih.gov.

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