Children with ADHD who take medication until adulthood may end up significantly shorter than their peers, according to new data from a long-term study — without a corresponding decrease in ADHD symptoms to make up for it.
The Multimodal Treatment Study (MTA) is a long-term follow-up study — funded by the National Institute of Mental Health (NIMH) — that began as a 14-month trial comparing the efficacy of medication and behavior therapy as childhood ADHD treatments. After its primary results were published in 1999, the study continued as an observational study, with follow-up assessments taking place every two years. The study focuses on 515 patients with ADHD — who were between the ages of seven and nine when the study first started — along with 289 control subjects of the same age.
The latest results, published March 10 in the Journal of Child Psychology and Psychiatry, showed that the (now adult) patients who had continued to take stimulant medication to treat their ADHD were, on average, 2.36 centimeters shorter than their counterparts with ADHD who had stopped taking medication or who took it only periodically. But the two groups showed no difference in symptom severity — though members of the former had, on average, taken more than 100,000 mg. of stimulant medication over the course of their lifetimes.