Children diagnosed with attention-deficit/hyperactivity disorder, commonly known as ADHD, and treated with common stimulants may be slightly more likely to gain weight and be slightly shorter in height by the time they reach adulthood. Although the magnitude of these physical changes remains small, the results suggest that physicians should regularly monitor the physical growth of children receiving this treatment. The study was published in the journal JAMA network open.
ADHD is a condition that affects people’s behavior, concentration, and impulse control. For many children, doctors prescribe a drug called methylphenidate to manage these behavioral symptoms. Methylphenidate is a stimulant that works by changing the balance of certain chemicals in the brain.
This drug is widely recognized as a highly effective and safe treatment that helps young people succeed in their daily lives. Despite its effectiveness, medical experts have raised questions about what effects this drug may have on physical development over the long term. Some previous reports suggested a potential link between stimulants and altered growth rates in childhood.
The researchers wanted to know whether these physical changes simply disappear over time, or whether they persist into adulthood. Children with this behavioral condition often experience difficulties that can independently affect their physical health. For example, you may have irregular eating habits, struggle to get enough physical activity, or have poor sleep quality.
Sleep is especially important for growing children because the human body releases most of its growth hormone during deep sleep. If a child repeatedly lacks restful sleep, the effects of this hormone can slow down their overall growth rate. Adding stimulants like methylphenidate to the mix creates further fluctuations for the growing child.
This drug is well known to temporarily suppress appetite during the day. This suppression may cause the child to skip meals, leading to overeating in the evening when the medication wears off. Cycles of skipping meals and overeating can lead to weight gain over several years.
At the same time, not getting consistent calories during the day can limit the raw energy your child needs to grow taller. The physical stress of living with a behavioral disorder can also disrupt a child’s natural circadian rhythm over time. This ongoing stress affects how the body manages energy and balances basic metabolic functions.
Over several years, these small disruptions to the body’s internal clock can have a big impact on how a child gains weight. Researchers noted that the drug also works by increasing levels of a brain chemical called dopamine. Beyond its role in behavior and attention, dopamine interacts with brain structures that control growth hormone.
Repeated fluctuations in dopamine levels during childhood can create instability for optimal physical growth. To better understand these possibilities, a team of Korean researchers decided to examine long-term health records. The research team was led by Jihoon Song, a biomedical researcher based at Korea University College of Medicine.
Song and colleagues aimed to see whether childhood diagnosis of ADHD and use of methylphenidate changed BMI in people’s early 20s. Body mass index (BMI) is a standard medical calculation that uses a person’s height and weight to estimate total body fat. To conduct the study, the research team collected anonymized records from South Korea’s National Health Insurance System.
The researchers focused on two main groups of young people who were newly diagnosed with this behavioral disorder between 2008 and 2013. The main group included 12,866 prepubescent children aged 6 to 11 years. The second group included 21,984 adolescents aged 12 to 19 years.
The researchers matched each of these individuals with a control subject of exactly the same age, gender, and household income level who did not have the disease. This matching process helped ensure that comparisons between groups were as fair and accurate as possible. The team then looked at medical records to see which individuals had been prescribed methylphenidate.
They precisely calculated the number of days each patient took the drug over a four-year period from initial diagnosis. The researchers then waited for the data to catch up with the patients’ adulthood. Researchers looked at the results of national health checkups from 2018 to 2022, when participants were between 20 and 25 years old.
They recorded the final adult height and BMI of each person in the study. The results showed that there were clear differences in body weight between different groups of young people. Children diagnosed with the disease had a higher average BMI in adulthood compared to matched controls.
This weight difference was even more pronounced among children who took methylphenidate. When looking at clinical obesity rates, trends followed a similar course. In the asymptomatic control group, just 35% of adults were classified as overweight or obese.
Among adults diagnosed in childhood but not taking medication, overweight and obesity rates rose to just over 43 percent. The percentage of people who were diagnosed and actively received treatment with stimulants reached 46.5%. Researchers also noticed a link between the amount of medication taken and final adult weight.
Children who took the drug for more than a year had higher BMI scores than those who took it for less than a year. Total dose over time directly matched the likelihood of gaining weight in adulthood. Regarding height, the results were slightly different.
For children with ADHD who did not take medication, the difference in final adult height was not statistically significant when compared to the control group. In other words, simply having the disease does not seem to increase final adult height. However, children who actively took methylphenidate showed a visible decrease in their final adult height.
Similar to the weight results, height loss was also related to treatment duration. Those who took the drug for longer periods experienced a slightly greater reduction in final height. Although these height reductions were measurable in the data, they were incredibly small in practical terms.
For example, women who took the drug for more than a year during childhood were only about 0.6 centimeters shorter on average than women in the control group. This difference is only a few inches, far below the standard threshold that doctors consider physically dangerous. The research team also looked at a group of older adolescents diagnosed between the ages of 12 and 19.
Because these teens had already completed most of their physical growth, drug treatment had a much smaller effect on their final height and weight as adults. Physical changes were most noticeable in children who started taking the drug before they hit puberty. The researchers noted some limitations to their study.
Because this is an observational study based on existing medical records, the researchers cannot conclusively prove that the drug directly caused changes in weight and height. Research designs can only show correlations between treatments and physical outcomes. Health records also lacked certain information that could affect the child’s development.
For example, the researchers didn’t have access to the heights and weights of the participants’ parents, which are big factors in determining a person’s adult size. There was also a lack of detailed information about the participants’ daily diet, exercise habits, and exact sleep schedules over the years. The research team emphasized that parents and patients should not abandon this effective treatment based on these findings.
The behavioral and academic benefits of managing this condition are well established and typically exceed a fraction of a centimeter of height. Instead, the authors recommend that pediatricians simply closely monitor their patients’ physical development. If a child taking this medication begins to show signs of slowed growth or excessive weight gain, your doctor can give you lifestyle advice.
Simply counseling your family about balanced nutrition, regular exercise, and healthy sleep habits can offset these mild physical effects. For children who are already at high risk for growth retardation, doctors may consider adjusting the dosage of the drug. Future research could focus on tracking patients’ daily habits to see exactly how lifestyle choices interact with the drug.
The researchers hope to develop more specific medical guidelines for monitoring the metabolic health of children receiving long-term stimulant treatment. Until then, basic awareness and regular pediatrician visits remain the best tools to keep your growing child healthy.
The study, “ADHD and methylphenidate use in preadolescent children, BMI and height in adulthood,” was authored by Jihun Song, Sun Jae Park, Jiwon Yu, Jina Chung, Seogsong Jeong, and Sang Min Park.
