A new study conducted by researchers at the Medical Center shows that the use of medication for attention deficit hyperactivity disorder has no long-term effects on brain function. As many as 5 to 7 percent of elementary school children are diagnosed with ADHD, a behavioral disorder that causes inattention, hyperactivity, impulsivity, or a combination of these symptoms. Many of these children are treated with psychostimulant medications, and while physicians and scientists alike know a great deal about how these medications work and how effective they are, little is known about their long-term effects. D., chairman, professor and senior professor in the Department of Physiology and Pharmacology at the Medical Center, and colleagues conducted an animal study to clarify the possible long-term effects of the drugs. The results of their study were surprising. “We know that the drugs used to treat ADHD are very effective, but the long-term effects of these drugs have been of great concern.” We don’t know if long-term use of these drugs will somewhat impair brain development or lead to subsequent substance abuse in adolescence.” The researchers studied 16 adolescent, non-human primates that were the equivalent of humans between the ages of 6 and 10. Eight animals were in the control group and received no medication, while the other eight received therapeutic doses of Ritalin extended-release, or methylphenidate, for more than a year, which is the equivalent of four years in children. Before and after the study, the brains of both groups of animals were imaged to measure changes in brain chemistry and structure. Researchers are also looking for developmental milestones to address the possible adverse effects of ADHD medications on physical growth and development. Once the MPH treatment and imaging studies were completed, these animals had the opportunity to self-administer cocaine for several months. Nader measured their penchant for acquiring drugs and observed the rate and amount to provide an index of susceptibility to substance abuse in adolescence. As the research paper reports, they found no difference between the two groups – monkeys treated with Ritalin during adolescence were no more susceptible to drug use afterward than the control animals drug. ”One year after drug treatment, we found no long-term lasting effects on brain neurochemistry and no changes in the structure of the developing brain. There was also no increased susceptibility to drug abuse in later adolescence.” “We were very careful in giving the same doses of drugs in children. This is one of the great strengths of our study, namely its direct translational application to children.” Non-human primates provide a special model for developmental studies because they go through relatively long childhoods and adolescence that are branded by hormones and physical maturation like humans do. She says, “Our study shows that long-term use of medication for ADHD does not have long-term negative effects on the developing brain, and at the same time, it does not put children at risk for subsequent adolescent substance abuse.” One of the exciting things about this study is that Hopkins conducted a “sister” study using slightly older animals and different drugs at the same time, and their findings were similar. “We were very confident in the results because we replicated each other’s studies in the same time frame and got the same results,” she said. “We think that’s pretty strong and reassuring.”