Drugs used to treat Attention Deficit Hyperactivity Disorder (ADHD) do not pose any significant long-term risks to the brain, new laboratory research suggests.
Wake Forest Baptist Medical Center scientists who conducted the study called the findings “surprising” and said they should be reassuring to the families of the nearly seven percent of elementary school children diagnosed with ADHD.
"We know that the drugs used to treat ADHD are very effective, but there have always been concerns about the long-lasting effects of these drugs," said researcher Linda Porrino, chair of Wake Forest’s Department of Physiology and Pharmacology. "We didn't know whether taking these drugs over a long period could harm brain development in some way or possibly lead to abuse of drugs later in adolescence."
ADHD, a behavioral disorder, causes problems with inattentiveness, over-activity and impulsivity. Many children with ADHD are treated with stimulant drugs. To determine the potential long-term effects of such drugs, Porrino and colleagues studied 16 primates treated with Ritalin, or methylphenidate (MPH), for more than a year.
Researchers took images of the animals' brains before and after the study to measure brain chemistry and structure. They also examined developmental milestones to address concerns that ADHD drugs adversely affect physical growth.
At the study’s completion, they found no differences between monkeys treated with Ritalin and a similar group of untreated primates.
"We found no long-lasting effects on the neurochemistry of the brain, no changes in the structure of the developing brain," Porrino said. "We were very careful to give the drugs in the same doses that would be given to children. That's one of the great advantages of our study is that it's directly translatable to children."
Porrino said non-human primates are good models for developmental research because they undergo relatively long childhood and adolescent periods marked by hormonal and physiological maturation much like humans.
The study, published in the journal Neuropsychopharmacology, was funded by the National Institute of Drug Abuse of the National Institutes of Health.