TOPLINE:

Children with attention-deficit/hyperactivity disorder (ADHD) treated with methylphenidate had a higher BMI and slightly shorter height in adulthood than children without ADHD. Prolonged use of methylphenidate was associated with an increased risk for obesity and reduced height.

METHODOLOGY:

• Researchers conducted a retrospective cohort study using data from the National Health Insurance Service of South Korea to evaluate the effect of methylphenidate use in children and adolescents with ADHD on their BMI and height in adulthood.
• They included 12,866 children aged 6-11 years (27.5% girls) and 21,984 adolescents aged 12-19 years (33.4% women) who were diagnosed with ADHD between 2008 and 2013. Participants were matched with control children and adolescents without ADHD by age, sex, and income level.
• Exposure to methylphenidate was assessed on the basis of prescriptions after diagnosis of ADHD. Cumulative exposure to methylphenidate was evaluated over a 4-year period and categorized as less than 1 year and less than 4 years.
• The primary outcomes were obesity (based on BMI) and height in adulthood, assessed according to the criteria of the World Health Organization and Korean standards, with short stature as mean height less than 174.4 cm for men and less than 161.8 cm for women.

TAKEAWAY:

• Children with ADHD had a higher adjusted mean BMI than control children (24.3 vs 23.3; P < .001). Male patients with ADHD on methylphenidate had an adjusted mean BMI of 25.4, with the highest adjusted mean BMI of 26 observed in those treated for 1-4 years. Similar outcomes were observed among adolescents with ADHD on methylphenidate.
• Children with ADHD who received methylphenidate had greater odds of being overweight than those without ADHD (adjusted odds ratio [aOR], 1.60; P < .001). The adjusted odds of being overweight were 1.51 among those with ADHD and 1.43 for non-methylphenidate users (P < .001 for both).
• The risk for overweight and obesity was higher in children who received methylphenidate than in those who did not receive it (aOR, 1.13; P = .001). Similar findings were noted for the risk for severe obesity (aOR, 1.88; P < .001).
• Height differences were not significant between children with and without ADHD, but the use of methylphenidate was linked to a slight reduction in height (P = .01) and increased odds of having short stature (aOR, 1.08; P = .01).

IN PRACTICE:

“Clinicians should be aware of its potential association with growth trajectories. Routine monitoring of weight and height, along with counseling on nutrition and physical activity, may help mitigate adverse outcomes. To promote optimal growth, management strategies such as improved sleep quality with sufficient sleep duration, balanced nutritional intake, and regular physical activity should be considered, rather than modifying treatment strategies,” the researchers wrote.

SOURCE:

The study was led by Jihun Song, PhD, of the Department of Biomedical Informatics at the Korea University College of Medicine in Seoul, South Korea. It was published online on January 5, 2026, in JAMA Network Open.

LIMITATIONS:

Factors such as parental BMI, genetic variance, and lifestyle behaviors were not fully accounted for. Only individuals who underwent health examinations were included.

DISCLOSURES:

The study was supported by grants from Korea University and the National Research Foundation of Korea. No relevant conflicts of interest were disclosed by the authors.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.