Objective: The purpose of this study was to investigate the effect of methylphenidate (MPH) on growth in Korean children and adolescents with attention-deficit/hyperactivity disorder (ADHD).
Methods: The medical records of 157 subjects (mean age 8.9±2.2 years; 134 boys) with ADHD who received treatment with MPH for at least 1 year at the Department of Psychiatry at Asan Medical Center were retrospectively reviewed. Height and weight were prospectively obtained and retrospectively gathered. Height and weight were converted to age- and gender-corrected standard scores (z scores) using norms from the Korean population. Growth changes were analyzed from the starting to the end of treatment using random coefficients models with change in weight or height z score as the dependent variable.
Results: Weight (β = -0.109, p<0.001) and height (β = -0.072, p<0.001) z scores significantly decreased during treatment. Weight z score decreased more in girls (β = -0.247, p<0.001) than in boys (β = -0.090, p<0.001). Weight z score decreased during the 1st year of medication (β = -0.327, p<0.001 for boys; β = -0.646, p<0.001 for girls), and did not change or increase after the 1st year. Height z score significantly decreased during treatment (β = -0.072, p<0.001) after controlling for the effect of age at treatment, gender, mean daily mg/kg dose, and comorbid depressive disorder. Height z score also decreased during the 1st year of medication (β = -0.089, p<0.001) but did not change after the 1st year.
Conclusions: These results suggest that MPH could be related to weight and height deficit in Korean children and adolescents, although the effects were minor, and disappeared after the 1st year. Because of the limitations of this study such as retrospective design, selection bias, and high attrition rate, further prospective studies are needed.