Long-term effects of ADHD medication on adult height: results from the NESARC.

To the Editor: Methylphenidate is the most commonly prescribed medication to treat attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. The long-term impact of methylphenidate on adult height remains debated1 because a significant negative impact on children’s growth has been suggested. The Multimodal Treatment Study of ADHD showed that children receiving methylphenidate had heights of 0.17 standard deviations below the population mean at the age of 9 years.2 It has been suggested that height velocity is negatively affected by methylphenidate early in the treatment period, with a normalized growth later on.3 As evidence, Biederman et al4 found no significant association between adult height and methylphenidate in a longitudinal study of 124 patients treated for ADHD during childhood. To our knowledge, this association has never been examined in a larger sample of adult individuals with a lifetime diagnosis of ADHD.