Child Health
Our growth velocity guide explains how to tell whether a child is growing at a healthy pace, and our guide on when to worry about a child's height covers the warning signs of growth failure in general. This piece answers a narrower question many parents ask before or during ADHD treatment: do stimulant medications slow growth, and do they change how tall a child ends up as an adult? It covers why the concern exists, what the long-term studies actually found, where they disagree, and what monitoring looks like in practice.
How Much Height Difference Have Long-Term Studies Found?
Height gaps reported for children treated with stimulants, from the two largest long-term follow-ups
Why Doctors Watch Growth on ADHD Medication
Decreased appetite and reduced weight gain are listed side effects of stimulant medications. Eating less during the day is the most widely cited explanation for slower growth, especially early in treatment.
Stimulants raise dopamine levels in the brain, and researchers have proposed that this may briefly affect growth hormone signaling. This mechanism is a hypothesis rather than an established explanation.
Concern about stimulants and growth dates back to studies in the 1970s, and it is serious enough that FDA prescribing information for methylphenidate includes a specific warning about long-term suppression of growth. The label tells prescribers to closely monitor height and weight in children taking stimulants and notes that a child who is not growing or gaining weight as expected may need treatment interrupted. That is a monitoring instruction, not a reason to avoid treatment, and it is the foundation for how most pediatricians handle the issue.
What the Research Shows in the First Few Years
The clearest and most consistent finding is a modest slowdown early in treatment. Here is the pattern the evidence describes.
Methylphenidate or an amphetamine-based medication
The biggest weight effect appears in the first 12 months
Concentrated in the first 24 to 30 months
Long-term studies disagree on lasting effects
That 2021 meta-analysis, published in Neuroscience and Biobehavioral Reviews, concluded that long-term methylphenidate can reduce height and weight but that the effect sizes are small and may have minimal clinical impact for most children. FDA labeling puts the early effect in concrete terms: in children aged 7 to 10 who were followed for three years in the MTA study, those medicated seven days a week throughout the year grew about 2 cm less in height and gained about 2.7 kg less weight than unmedicated children, without evidence of a growth rebound during that period. The label adds that published data on amphetamines are more limited, but a similar effect is expected.
The Adult Height Question: Two Major Studies Disagree
Whether the early slowdown is temporary or permanent is where the evidence splits. The two largest long-term follow-ups reached different conclusions.
The Multimodal Treatment Study of ADHD (MTA) began as a randomized trial and then followed participants into adulthood. By about age 25, children who had used stimulants consistently or inconsistently were 2.55 cm shorter than those with negligible use, and consistent users were 2.36 cm shorter than inconsistent users. A later analysis of growth trajectories across 16 years found the consistent-use group, only 53 participants, ended up 4.06 cm (1.6 in) shorter than the negligible-use group. The researchers also reported that this extended medication use was not associated with lower symptom severity in adulthood, which they framed as a reason to weigh benefits and costs over time.
The Rochester study, published in Pediatrics in 2014, took a different approach. It followed 340 children with ADHD and 680 matched controls from a population-based birth cohort in Minnesota, using medical records and adult follow-up. Neither ADHD nor stimulant treatment was linked to differences in the size of the adolescent growth spurt or in adult height, and longer treatment wasn't associated with shorter adult height. Among boys, a longer duration of stimulant use before the growth spurt was linked to a later spurt, which our peak height velocity guide explains in more detail, but adult height still did not differ.
Why the studies can disagree. No trial has randomly assigned children to years of stimulant treatment versus none, so the long-term evidence is observational. In the MTA follow-up, families chose whether to continue medication after the original trial, and families who kept their child on treatment may differ in ways that also relate to growth. The consistent-use group was small. The Rochester cohort relied partly on medical records from children born between 1976 and 1982, when treatment patterns may have differed from today's. Both are credible studies, and the honest summary is that a lasting effect of around 1 to 1.5 inches is possible for children who stay on stimulants continuously for many years, but it has not been consistently shown.
What Parents Can Do
The goal is to catch a growth slowdown early, when there are the most options, without giving up treatment that helps. These are the practical steps that follow from the evidence.
What about "drug holidays"? Some families pause stimulants on weekends or during school vacations. A 2015 review of 22 studies published between 1972 and 2013 found that 25% to 70% of families take such breaks, most often during school holidays, and reported some evidence that longer breaks were linked to better growth, while shorter breaks could help with sleep and appetite. The evidence is limited and mixed in quality, and breaks can bring back symptoms at home and in activities. A planned break is a reasonable topic to raise with your child's prescriber, especially if growth or appetite is a concern, but it should be a shared decision rather than a default.
What This Means For You
The practical takeaway: ADHD stimulants can slow growth a little, mostly in the first one to three years, and that early effect is well documented. Whether it leaves a lasting difference is unsettled: one major study found consistent long-term users ended up about 1 to 1.6 inches shorter, while another found no difference in adult height. Either way, the answer for most families is careful monitoring rather than avoiding treatment. Track your child's height accurately with our home measuring guide, check the yearly rate with our growth velocity guide, and if growth is slowing for any reason, see our guide on when to worry about a child's height.
Frequently Asked Questions
Does ADHD medication stunt growth?
It can slow growth modestly, mostly in the first one to three years. FDA labeling for methylphenidate describes about 2 cm less height gain over three years in children medicated seven days a week. Whether this affects adult height is unsettled: the MTA study found consistent long-term users ended up about 2.4 to 4 cm shorter, while a population-based Rochester study found no difference.
Will my child catch up in height after stopping ADHD medication?
The evidence is mixed. FDA labeling notes that children in the MTA study showed no growth rebound during the three-year period it describes, and the MTA's adult follow-up suggested some of the difference persisted. The Rochester cohort found no difference in adult height, which is consistent with catch-up. A 2015 review reported some evidence that longer breaks from medication were linked to better growth.
Do non-stimulant ADHD medications affect growth?
Most of the long-term growth research described here involves stimulants, especially methylphenidate. Non-stimulant options exist, and a prescriber can explain how each one's side effects, including any effect on appetite or weight, compare for your child's situation.
How often should my child's growth be checked on ADHD medication?
FDA labeling tells prescribers to closely monitor height and weight in children taking stimulants. In practice, that usually means measuring at every medication follow-up and plotting the results on a growth chart so changes in growth rate are visible over time. Ask your child's doctor what schedule they recommend.
Should we take weekends or summers off ADHD medication to protect growth?
Some families do, and a 2015 review found some evidence that longer breaks were linked to better growth. The evidence is limited, and breaks can bring back symptoms that affect home life, friendships, and activities. It's a reasonable option to discuss with the prescriber, particularly if growth or appetite is a concern, rather than a step to take on your own.
