September 2, 2014 | Steven Reinberg
"Stimulant medication did not affect children's final height as adults," said study researcher Dr. Slavica Katusic, an associate professor of pediatrics at the Mayo Clinic in Rochester, Minn.
Katusic noted that results of earlier studies have been mixed, with some showing these drugs retard growth and others showing they don't. But, most of the previous studies had limitations, such as having too few children or spotty information about adult height, she said.
Katusic said this study is unique because it followed a group of people with ADHD who were taking stimulant medications and compared them with a group with ADHD who were not taking medication and also a group that didn't have ADHD. These individuals were followed from childhood to adulthood, she said.
ADHD is one of the most common disorders of childhood, according to the U.S. National Institute of Mental Health (NIMH). Symptoms include difficulty paying attention or staying focused on one task, overactivity and impulsive behavior, the NIMH explains.
Stimulant medications are a mainstay of ADHD treatment, and while it may seem odd to use stimulant medication on an overactive child, stimulant drugs have a calming, focusing effect on youngsters with ADHD, according to the NIMH. Katusic said these drugs are important for improving school and social functioning.
Katusic's team studied 340 children with ADHD and 680 without the condition. "We compared the height when they were children and when they were grown up," she said.
The average follow-up time was 26 years for those with ADHD and 23 years for people without ADHD. Approximately 70 percent of those with ADHD who completed the study had taken stimulant medication for more than three months, the researchers noted.
There was no difference in adult height between those who took ADHD drugs and those who didn't, the investigators found.
"Neither childhood ADHD itself nor stimulant medication was associated with shorter stature as adults," Katusic said.
Boys with ADHD who were treated with stimulants for three or more months had a later growth spurt than boys who didn't take these drugs, but there was no difference in the size of the growth spurt, the researchers noted.
In addition, no connection was seen between the amount of time a child took stimulant drugs and adult height, the study authors found.
"But despite our findings, doctors should monitor growth when making medication decisions," she said. "Our study says don't worry at all, but human beings are all different and you always have to be careful."
The report was published online Sept. 1 in the journal Pediatrics.
Dr. Marcel Deray, a pediatric neurologist at Miami Children's Hospital, said, "This is good news, because we discuss this issue with parents of kids with ADHD."
Deray hopes the study will be replicated to prove the point that these stimulants don't affect height. "It would good to have a couple of studies showing the same thing," he said.
He also said this finding should be reassuring to parents who may be reluctant to allow their children to use these drugs because of the potential risk of stunting their child's growth.