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Extended use of stimulants to treat -deficit hyperactivity disorder ( ) from into adulthood may result in suppressed adult height without reduced symptoms of ADHD, according to a new follow-up study published March 10 in The Journal of Child Psychology and .

In the 1990s, the National Institute of Mental Health (NIMH) funded a massive randomized clinical trial designed to evaluate the effectiveness of the leading treatments for ADHD called the “Multimodal Treatment of Attention Deficit Hyperactivity Disorder (MTA) Study".

The primary findings of the MTA study—which compared the effectiveness of pharmacological and behavioral for treating ADHD in 579 children (7-10 years of age)—were published in 1999. Since then, longitudinal follow-up data (such as the latest suppressed height findings reported this week) continue to be published.

The MTA authors of the new study conclude that the short-term treatment of ADHD with may be justified in some cases. However, the long-term consequences of pharmacological treatments for ADHD are associated with growth-related costs that may not justify the symptom-related benefits in the long run.

James M. Swanson from the University of California, Irvine is the corresponding author of this study, which has a total of 30 co-authors—from prestigious universities such as Stanford, Duke, Columbia, Berkeley, McGill, NYU and Mt. Sinai—who are all part of the MTA Cooperative Group. The authors of this study write:

"The most recently published guidelines (American Academy of Pediatrics, 2011) recommend expanding the diagnosis and treatment beyond school-aged children and using stimulant medication as first-line treatment for adolescents as well as school-aged children. Since this would increase the average duration of treatment and cumulative ME dose of medication in some individuals, the findings suggest growth-related costs may increase."

In December 2013, I wrote a Psychology Today post, "Are Pharmaceuticals the Answer for Treating ADHD?" My blog post was inspired in part by the study, "Trends in the Parent-Report of Health Care Provider-Diagnosed and Medicated Attention-Deficit/Hyperactivity Disorder: United States, 2003–2011" from the January 2014 Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP). The conclusion of this study stated:

"Approximately 2 million more U.S. children/adolescents aged 4 to 17 years had been diagnosed with ADHD in 2011, compared to 2003. More than two-thirds of those with current ADHD were taking medication for treatment in 2011."

In my 2013 PT blog post, I conclude, "There are clearly cases when pharmaceuticals dramatically improve a person’s physical and mental health. Every individual and parent must remain vigilant about knowing when medication is going to be beneficial in both the short and long-term."

Based on the latest findings from the MTA Cooperative Group, extended use of medication to treat ADHD is associated with suppression of adult height by age 25, but not a reduction of symptom severity. For anyone who wants to achieve his or her full height by adulthood, the long-term outcomes of extended ADHD medication use probably aren't worth the growth-related costs.