Effects of methylphenidate on body index and physical fitness in Korean children with attention deficit hyperactivity disorder.

OBJECTIVE The side effects of methylphenidate (MPH) on growth remain a controversial concern. This study aimed to investigate the effect of MPH on clinical symptoms, growth, and physical fitness in Korean children. METHODS Fifty male children with attention deficit hyperactivity disorder (ADHD) treated with methylphenidate (MPH-ADHD), 69 MPH-naïve male children with ADHD (Naïve-ADHD), and 60 age-matched and sex-matched healthy control subjects were recruited. Intelligence quotient (IQ), clinical symptoms of ADHD, body index (height, weight, and body mass index [BMI]), and physical fitness (muscular strength, endurance, flexibility, agility, speed, and balance) were assessed. RESULTS Total IQ and performance IQ scores were significantly different among the three groups, as were mean Korean Attention Deficit Hyperactivity Disorder (K-ARS)-total, K-ARS-inattention, and K-ARS-hyperactivity scores. There was no significant difference in height, weight, or BMI among the three groups. There were significant differences in skill-related fitness scores for balance (healthy controls > MPH-ADHD > Naïve-ADHD) and agility shuttle test time (healthy controls < MPH-ADHD < Naïve-ADHD). CONCLUSIONS Our findings support the effectiveness of MPH treatment for improving IQ, attention, and balance and agility measures of skill-related fitness in Korean children with ADHD. MPH was not associated with growth delays in height, weight, and BMI.