LACK OF EFFECT OF METHYLPHENIDATE ON SERUM GROWTH-HORMONE (GH), GH-BINDING PROTEIN, AND INSULIN-LIKE-GROWTH-FACTOR-I

The aim of this study was to assess the growth hormone (GH) axis in me thylphenidate (MPH)-treated and untreated boys with attention-deficit and hyperactivity disorder (ADHD), by evaluating serum GH, GH-binding protein (GHBP) activity, and Insulin-like growth factor I (IGF-I) leve ls as compared to age-matched normal controls. Blood samples were take n from 42 boys (aged 6-16 years) diagnosed as having ADHD according to DSM-III-R criteria and confirmed by using the Schedule for Affective Disorder and Schizophrenia for school-age children (K[Kiddle]-SADS), A total of 21 patients were treated with MPH (5-20 mg/day; 0.15-0.77 mg /kg/day), on a drug holiday protocol, for 1-36 months, and 21 were dru g naive. A total of 46 age-matched normal boys at height and weight wi thin normal range served as controls. No significant differences were detected bt tween the MPH-treated ADHD children, the untreated ADHD ch ildren. and the control children on fasting serum GH levels, GHBP acti vity, or IGF-I levels. Active treatment with MPH, in ADHD children on a drug holiday protocol, does not cause changes in GH axis as manifest ed by normal values of GH, GHBP, and IGF-I.