ADHD medications can slow down the growth of teenage boys, according to new Australian research published this week in the MJA.
The researchers from the University of Sydney found male teens who took methylphenidate or dexamphetamine for more than three years were likely to be shorter and slimmer than their classmates.
The study involving 65 boys aged 12 to 16-years-old who had been taking the stimulant medication for over three years and 174 controls, found boys aged 12 to 14 with ADHD had significantly lower weight and body mass index but comparable height and pubertal development.
But boys aged 14 to 16 with ADHD had the trifecta: markedly lower body weight as well as significant delays in height and pubertal development, wrote the lead author Dr Alison Poulton and colleagues.
And the higher the stimulant dose, the slower the height growth, the authors reported.
“These findings suggest that stimulant medication delays the rate of maturation during puberty, including the timing of the peak height velocity, but not the onset of puberty,” they wrote.
The study backs a 2007 US report, which found ADHD drugs slowed children’s growth rate.
But with no control group of children with untreated ADHD, the authors could not definitively determine whether the effect was due to ADHD or the medication, though the dose relationship between stimulant and height seems to suggest the latter.
“However, this finding could also be explained if children with more severe ADHD develop more slowly and if the dose of medication is only a marker of severity of ADHD,” they conceded.
The authors recommended that boys on ADHD medication should take as low a dose as possible to maintain an adequate rate of growth during puberty.
As first appeared in Psychiatry Update, 23 January 2013.